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Hypothesis: The physical and mechanical properties of triacylglycerols (TAGs), or 'fats', depend on their composition and thermal history which, in turn, impact crystal structure and morphology. We examine whether thermal history can be mechanistically related to film removal by a surfactant solution., Experiments: Model TAG mixtures, comprising triolein:tripalmitin:tristearin 0.5:0.3:0.2, were subjected to a range of cooling profiles from the melt (0.5-80°C/min, Newtonian and annealed), and the resulting solid films characterised by microscopy, X-ray diffraction, infrared spectroscopy, and contact angle measurements. Film removal from a model glass substrate by an aqueous surfactant solution of sodium dodecylsulphate and dodecyldimethylamine oxide at room temperature fixed at 25°C was examined under quiescent flow conditions., Findings: Quantitative relations are established between TAG cooling profile, crystal structure and morphology, surface energy γ SFE , and removal (or 'cleaning'). In general, films cooled slowly from the melt yield heterogeneous morphologies with predominantly β 1 ' phase, higher polar γ SFE , and faster removal timescales. By contrast, rapid cooling results in homogeneous films, rich in β 2 ' phase, low polar γ SFE , and long removal times. Our results elucidate the non-trivial impact of TAG thermal history, connecting the multiscale semi-crystalline structure to surface energy, and eventually to film delamination by micellar solutions., Competing Interests: Declaration of Competing Interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Joao Cabral reports financial support was provided by Engineering and Physical Sciences Research Council. Joao Cabral reports financial support was provided by Royal Academy of Engineering. Joao Cabral reports financial support was provided by The Procter & Gamble Company. Joao Cabral reports financial support was provided by The Royal Society. One of the authors is employed by Procter & Gamble and is collaborating on a scientific capacity If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)

Cartilage acidic protein-1 (CRTAC1) is a secreted glycoprotein with roles in development, function and repair of the nervous system. It is linked to ischemic stroke, osteoarthritis and (long) COVID outcomes, and has suppressive activity in carcinoma and bladder cancer. Structural characterization of CRTAC1 has been complicated by its tendency to form disulfide-linked aggregates. Here, we show that CRTAC1 is stabilized by potassium ions. Using x-ray crystallography, we determined the structure of CRTAC1 to 1.6 Å. This reveals that the protein consists of a three-domain fold, including a previously-unreported compact β-propeller-TTR combination, in which an extended loop of the TTR plugs the β-propeller core. Electron density is observed for ten bound ions: six calcium, three potassium and one sodium. Low potassium ion concentrations lead to changes in tryptophan environment and exposure of two buried free cysteines located on a β-blade and in the β-propeller-plugging TTR loop. Mutating the two free cysteines to serines prevents covalent intermolecular interactions, but not aggregation, in absence of potassium ions. The potassium ion binding sites are located between the blades of the β-propeller, explaining their importance for the stability of the CRTAC1 fold. Despite varying in sequence, the three potassium ion binding sites are structurally similar and conserved features of the CRTAC protein family. These insights into the stability and structure of CRTAC1 provide a basis for further work into the function of CRTAC1 in health and disease., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

The design and synthesis of hybrid borates by the organic ligand modification method are urgent and undeveloped areas of research. It is difficult to directly integrate organoboronic acids within inorganic borate chemistry by adopting the traditional preparation approaches. This work reports a facile synthetic method to synthesize a large family of pyrazole molecule-protected borates in a rapid and precise manner under mild conditions. A unique cyclic eight-membered B4O4-ring has been identified as the cluster core for all these hybrid borates with two different conformations (boat and crown). This strategy can be applied to a system of pyrazolyl molecules to generate such hybrid borates in two independent routes from organoboronic or inorganic boric acids. Furtherly, the mechanism of 'click reaction' between boric acid and pyrazole induced by copper ions has been proposed based on the synthetic conditions and the structure of intermediate. Due to the bimetallic Cu sites and the functional surfaces, these materials can be used as electrocatalysts for CO2 reduction reaction and efficiently enhance the selectivity of HCOOH and C2H4. Our strategy can be regarded as a typical template technique for organic molecule-protected borates., (© 2024 Wiley‐VCH GmbH.)

Ferroelectric HfO 2 -based thin films have attracted much interest in the utilization of ferroelectricity at the nanoscale for next-generation electronic devices. However, the structural origin and stabilization mechanism of the ferroelectric phase are not understood because the film is typically nanocrystalline with active yet stochastic ferroelectric domains. Here, electron microscopy is used to map the in-plane domain network structures of epitaxially grown ferroelectric Y:HfO 2 films in atomic resolution. The ferroelectricity is confirmed in free-standing Y:HfO 2 films, allowing for investigating the structural origin for their ferroelectricity by 4D-STEM, high-resolution STEM, and iDPC-STEM. At the grain boundaries of <111>-oriented Pca2 1 orthorhombic grains, a high-symmetry mixed-( R 3 m , Pnm2 1 ) phase is induced, exhibiting enhanced polarization due to in-plane compressive strain. Nanoscale Pca2 1 orthorhombic grains and their grain boundaries with mixed-( R 3 m , Pnm2 1 ) phases of higher symmetry cooperatively determine the ferroelectricity of the Y:HfO 2 film. It is also found that such ferroelectric domain networks emerge when the film thickness is beyond a finite value. Furthermore, in-plane mapping of oxygen positions overlaid on ferroelectric domains discloses that polarization is suppressed at vertical domain walls, while it is active when domains are aligned horizontally with subangstrom domain walls. In addition, randomly distributed 180° charged domain walls are confined by spacer layers.

Understanding the substrate specificity of carrageenases has long been of interest in biotechnology applications. So far, the structural basis of the βκ-carrageenase that hydrolyzes furcellaran, a major hybrid carrageenan, remains unclear. Here, the crystal structure of Cgbk16A&#95;Wf, as a representative of the βκ-carrageenase from GH16&#95;13, was determined, and the structural characteristics of this subfamily were elucidated for the first time. The substrate binding mode was clarified through a structure analysis of the hexasaccharide-bound complex and molecular docking. The binding pocket involves a conserved catalytic motif and several specific residues associated with substrate recognition. Functions of residues R88, E290, and E184 were validated through site-directed mutagenesis. Comparing βκ-carrageenase with κ-carrageenase, we proposed that their different substrate specificities are partly due to the distinct conformations of subsite -1. This research offers a comprehensive understanding of the recognition mechanism of carrageenases and provides valuable theoretical support for enzyme modification and carrageenan oligosaccharide preparation.

The theoretical predictions and experimental syntheses of hydrogen sulfide (H 3 S) have ignited a surge of research interest in hydride superconductors. Over the past two decades, extensive investigations have been conducted on hydrides with the ultimate goal of achieving room-temperature superconductivity under ambient conditions. In this review, we present a comprehensive summary of the current strategies and progress towards this goal in hydride materials. We conclude their electronic characteristics, hydrogen atom aggregation forms, stability mechanisms, and more. While providing a real-time snapshot of the research landscape, our aim is to offer deeper insights into reducing the stabilizing pressure for high-temperature superconductors in hydrides. This involves defining key long-term theoretical and experimental opportunities and challenges. Although achieving high critical temperatures for hydrogen-based superconductors still requires high pressure, we remain confident in the potential of hydrides as candidates for room-temperature superconductors at ambient pressure., (© 2024 IOP Publishing Ltd. All rights, including for text and data mining, AI training, and similar technologies, are reserved.)

The global spread of COVID-19 remains a significant threat to human health. The SARS-CoV-2 BQ.1.1 lineage, including BA.5.2, BF.7, BQ.1 and BQ.1.1, caused a new soaring of infection cases due to rapid transmission. However, the receptor binding mechanism and immune evasion capacity of these variants need to be explored further. Our study found that while the BA.5.2, BF.7 and BQ.1.1 variants pseudovirus had similar cell entry efficiency, the BF.7 and BQ.1.1 RBD bound to human ACE2 (hACE2) with a slightly stronger affinity than the BA.5.2 RBD. Structural analysis revealed R346T, K444T, and N460K mutations altered RBD-hACE2 binding interface details and surface electrostatic potential of BQ.1.1 RBD. Serum neutralization tests showed BQ.1.1 variant had stronger immune evasion capacity than BA.5.2 and BF.7 variants. Our findings illustrated the receptor binding mechanism and serological neutralization activity of the BA.5.2, BF.7 and BQ.1.1 variants, which verified the necessity for further antibody therapy optimization and vaccination development., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Inc.)

The SARS-CoV-2 coronavirus is characterized by high mutation rates and significant infectivity, posing ongoing challenges for therapeutic intervention. To address potential challenges in the future, the continued development of effective drugs targeting SARS-CoV-2 remains an important task for the scientific as well as the pharmaceutical community. The main protease (M pro ) of SARS-CoV-2 is an ideal therapeutic target for COVID-19 drug development, leading to the introduction of various inhibitors, both covalent and non-covalent, each characterized by unique mechanisms of action and possessing inherent strengths and limitations. Natural products, being compounds naturally present in the environment, offer advantages such as low toxicity and diverse activities, presenting a viable source for antiviral drug development. Here, we identified a natural compound, rosmarinic acid, which exhibits significant inhibitory effects on the M pro of the SARS-CoV-2. Through detailed structural biology analysis, we elucidated the precise crystal structure of the complex formed between rosmarinic acid and SARS-CoV-2 M pro , revealing the molecular basis of its inhibitory mechanism. These findings not only enhance our understanding of the antiviral action of rosmarinic acid, but also provide valuable structural information and mechanistic insights for the further development of therapeutic strategies against SARS-CoV-2., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

2C is a highly conserved picornaviral non-structural protein with ATPase activity and plays a multifunctional role in the viral life cycle as a promising target for anti-picornavirus drug development. While the structure-function of enteroviral 2Cs have been well studied, cardioviral 2Cs remain largely uncharacterized. Here, an endogenous ATP molecule was identified in the crystal structure of 2C from encephalomyocarditis virus (EMCV, Cardiovirus A). The ATP is bound into the ATPase active site with a unique compact conformation. Notably, the γ-phosphate of ATP directly interacts with Arg311 (conserved in cardioviral 2Cs), and its mutation significantly inhibits the ATPase activity. Unexpectedly, this mutation remarkably promotes 2C self-oligomerization and viral replication efficiency. Molecular dynamic simulations showed that the Arg311 side chain is highly dynamic, indicating it may function as a switch between the activation state and the inhibition state of ATPase activity. A hexameric ring model of EMCV 2C full length indicated that the C-terminal helix may get close to the N-terminal amphipathic helices to form a continuous positive region for RNA binding. The RNA-binding studies of EMCV 2C revealed that the RNA length is closely associated with the RNA-binding affinities and indicated that the substrate may wrap around the outer surface of the hexamer. Our studies provide a biochemical framework to guide the characterization of EMCV 2C and the essential role of arginine in cardioviral 2C functions., Importance: Encephalomyocarditis virus (Cardiovirus A) is the causative agent of the homonymous disease, which may induce myocarditis, encephalitis, and reproductive disorders in various mammals. 2C protein is functionally indispensable and a promising target for drug development involving broad-spectrum picornaviral inhibitors. Here, an endogenous ATP molecule with a unique conformation was discovered by a combination of protein crystallography and high-performance liquid chromatography in the encephalomyocarditis virus (EMCV) 2C structure. Biochemical and structural characterization analysis of EMCV 2C revealed the critical role of conserved Arg311 in ATPase activity and self-oligomerization of EMCV 2C. The viral replication kinetics and infectivity study suggested that the residue negatively regulated the infectivity titer and virus encapsulation efficiency of EMCV and is, therefore, crucial for 2C protein to promote viral replication. Our systemic structure-function analysis provides unique insights into the function and regulation mechanism of cardioviral 2C protein.

Docking domains (DDs) located at the C- and N-termini of polypeptides play a crucial role in directing the assembly of polyketide synthases (PKSs), which are multienzyme complexes. Here, we determined the crystal structure of a complex comprising the C-terminal DD ( C DD MlnB ) and N-terminal DD ( N DD MlnC ) of macrolactin trans-acyltransferase (AT) PKS that were fused to a functional enzyme, AmpC EC2 β-lactamase. Interface analyses of the C DD MlnB / N DD MlnC complex revealed the molecular intricacies in the core section underpinning the precise DD assembly. Additionally, circular dichroism and steady-state kinetics demonstrated that the formation of the C DD MlnB / N DD MlnC complex had no influence on the structural and functional fidelity of the fusion partner, AmpC EC2. This inspired us to apply the C DD MlnB / N DD MlnC assembly to metabolon engineering. Indeed, DD assembly induced the formation of a complex between 4-coumarate-CoA ligase and chalcone synthase both involved in flavonoid biosynthesis, leading to a remarkable increase in naringenin production in vitro., Competing Interests: Declaration of interests D.-W.B., E.K., B.-G.J., S.-J.Y., N.K.L., J.-S.H., S.-S.C., and Y.J.Y. have filed a patent for employing docking domains to assemble an artificial metabolon, as described in this study., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Phthalate esters (PAEs) are emerging hazardous and toxic chemicals that are extensively used as plasticizers or additives. Diethyl phthalate (DEP) and dimethyl phthalate (DMP), two kinds of PAEs, have been listed as the priority pollutants by many countries. PAE hydrolases are the most effective enzymes in PAE degradation, among which family IV esterases are predominate. However, only a few PAE hydrolases have been characterized, and as far as we know, no crystal structure of any PAE hydrolases of the family IV esterases is available to date. HylD1 is a PAE hydrolase of the family IV esterases, which can degrade DMP and DEP. Here, the recombinant HylD1 was characterized. HylD1 maintained a dimer in solution, and functioned under a relatively wide pH range. The crystal structures of HylD1 and its complex with monoethyl phthalate were solved. Residues involved in substrate binding were identified. The catalytic mechanism of HylD1 mediated by the catalytic triad Ser140-Asp231-His261 was further proposed. The hylD1 gene is widely distributed in different environments, suggesting its important role in PAEs degradation. This study provides a better understanding of PAEs hydrolysis, and lays out favorable bases for the rational design of highly-efficient PAEs degradation enzymes for industrial applications in future., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal, relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

The electrochemical oxidation of anodic metals (M = nickel and palladium) in an acetonitrile solution of the thiosemicarbazone ligands ( E )-2-(1-(4-methoxyphenyl)ethylidene)-N-methylhydrazine-1-carbothioamide (a), ( E )-2-(1-(p-tolyl)ethylidene)hydrazine-1-carbothioamide (b), and ( E )-N-phenyl-2-(1-(p-tolyl)ethylidene)hydrazine-1-carbothioamide (c) yielded the homoleptic complexes [ML 2 ], 1a , 1b , 1c , and 2c and [M 4 L 4 ], 2a as air-stable solids. The crystal structures for 1a , 1b , 1c , and 2c show the ligands in a transoid disposition with the [S,S] and [N,N] donor atom pairs occupying cis positions on the nearly square planar coordination plane of the metal. The structure for 2a of S4 symmetry comprises a tetranuclear palladacycle where the metalated ligands are arranged around a central Pd 4 S 4 environment: a crown ring with alternating palladium and sulfur atoms. The latter complex is the first example of an electrochemical preparation of a cyclometalated palladium compound, marking a milestone in the chemistry of such species. The compounds have been fully characterized by elemental microanalysis, mass spectrometry, infrared (IR), and 1 H nuclear magnetic resonance (NMR) spectra.

UDP- N -acetylglucosamine pyrophosphorylase (UAP) catalyzes the last step in the hexosamine biosynthesis pathway to directly produce UDP- N -acetylglucosamine (UDP-GlcNAc). Because UAPs play important physiological and pathological roles in organisms, they are considered potential targets for drug and pesticide development. However, the lack of efficient and selective inhibitors is a bottleneck that must be overcome. This study reports the first crystal structure of the insect UAP from Spodoptera frugiperda ( Sf UAP) in complex with UDP-GlcNAc. Sf UAP has two insect-specific structural characteristics in the active pocket, namely, a free Cys (Cys 334 ) and a Mg 2+ binding site, which differentiate it from human UAP ( Hs AGX1) and fungal UAP ( Af UAP) in terms of substrate and inhibitor binding. N -(4-Nitrophenyl)maleimide ( p NPMI) and myricetin are discovered as potent covalent and noncovalent inhibitors of Sf UAP, respectively. Moreover, myricetin can significantly reduce the level of cellular O -GlcNAcylation by inhibiting both UAP and O -GlcNAc transferase. These findings provide novel insights into the development of UAP-based drugs and pesticides.

The synthesis and structural characterization of four novel supramolecular hydrogen-bonded arrangements based on self-assembly from molecular `[Cu(2,2'-biimidazole)]' modules and malonate anions are presented, namely, tetrakis(2,2'-biimidazole)di-μ-chlorido-dimalonatotricopper(II) pentahydrate, [Cu 3 (C 3 H 2 O 4 ) 2 Cl 2 (C 6 H 6 N 4 ) 4 ]·5H 2 O or [Cu(H 2 biim) 2 (μ-Cl)Cu 0.5 (mal)] 2 ·5H 2 O, aqua(2,2'-biimidazole)malonatocopper(II) dihydrate, [Cu(C 3 H 2 O 4 )(C 6 H 6 N 4 )(H 2 O)]·2H 2 O or [Cu(H 2 biim)(mal)(H 2 O)]·2H 2 O, bis[aquabis(2,2'-biimidazole)copper(II)] dimalonatodiperchloratocopper(II) 2.2-hydrate, [Cu(C 6 H 6 N 4 ) 2 (H 2 O)] 2 [Cu(C 3 H 2 O 4 )(ClO 4 ) 2 ]·2.2H 2 O or [Cu(H 2 biim) 2 (H 2 O)] 2 [Cu(mal) 2 (ClO 4 ) 2 ]·2.2H 2 O, and bis(2,2'-biimidazole)copper(II) bis[bis(2,2'-biimidazole)(2-carboxyacetato)malonatocopper(II)] tridecahydrate, [Cu(C 6 H 6 N 4 ) 2 ][Cu(C 3 H 2 O 4 )(C 3 H 3 O 4 )(C 6 H 6 N 4 ) 2 ]·13H 2 O or [Cu(H 2 biim) 2 ][Cu(H 2 biim) 2 (Hmal)(mal)] 2 ·13H 2 O. These assemblies are characterized by self-complementary donor-acceptor molecular interactions, demonstrating a recurrent and distinctive pattern of hydrogen-bonding preferences among the carboxylate, carboxylic acid and N-H groups of the coordinated 2,2'-biimidazole and malonate ligands. Additionally, coordination of the carboxylate group with the metallic centre helps sustain remarkable supramolecular assemblies, such as layers, helices, double helix columns or 3D channeled architectures, including mixed-metal complexes, into a single structure.

MpaG' is an S-adenosyl-L-methionine (SAM)-dependent methyltransferase involved in the compartmentalized biosynthesis of mycophenolic acid (MPA), a first-line immunosuppressive drug for organ transplantations and autoimmune diseases. MpaG' catalyzes the 5-O-methylation of three precursors in MPA biosynthesis including demethylmycophenolic acid (DMMPA), 4-farnesyl-3,5-dihydroxy-6-methylphthalide (FDHMP), and an intermediate containing three fewer carbon atoms compared to FDHMP (FDHMP-3C) with different catalytic efficiencies. Here, we report the crystal structures of S-adenosyl-L-homocysteine (SAH)/DMMPA-bound MpaG', SAH/FDHMP-3C-bound MpaG', and SAH/FDHMP-bound MpaG' to understand the catalytic mechanism of MpaG' and structural basis for its substrate flexibility. Structural and biochemical analyses reveal that MpaG' utilizes the catalytic dyad H306-E362 to deprotonate the C5 hydroxyl group of the substrates for the following methylation. The three substrates with differently modified farnesyl moieties are well accommodated in a large semi-open substrate binding pocket with the orientation of their phthalide moiety almost identical. Based on the structure-directed mutagenesis, a single mutant MpaG' Q267A is engineered with significantly improved catalytic efficiency for all three substrates. This study expands the mechanistic understanding and the pocket engineering strategy for O-methyltransferases involved in fungal natural product biosynthesis. Our research also highlights the potential of O-methyltransferases to modify diverse substrates by protein design and engineering., (© 2024 The Protein Society.)

A long-standing issue about the correct identification of an important starting reagent, iron(III) hexafluoroacetylacetonate, Fe(hfac) 3 (1), has been resolved. The tris-chelated mononuclear complex was found to crystallize in two polymorph modifications which can be assigned as the low-temperature (1-L) monoclinic P2 1 /n and the high-temperature (1-H) trigonal P-3. Low-temperature polymorph 1-L was found to transform to 1-H upon sublimation at 44 °C. Two modifications are clearly distinguished by powder X-ray diffraction (PXRD), single-crystal X-ray diffraction, differential scanning calorimetry (DSC), and melting-point measurements. On the other hand, the two forms share similar characteristics in direct analysis in real-time mass spectrometry (DART-MS), attenuated total reflection (ATR) spectroscopy, and some physical properties, such as color, volatility, sensitivity, and solubility. Analysis of the literature and some of our preliminary data strongly suggest that the appearance of two polymorph modifications for trivalent metal (both transition and main group) hexafluoroacetylacetonates is a common case for several largely used complexes not yet accounted for in the crystallographic databases.

During the course of exploring crystallization conditions in generating metal-organic frameworks (MOFs) for use in the crystalline sponge method, two discrete metal-organic complexes, namely, aqua[2,4,6-tris(pyridin-4-yl)-1,3,5-triazine]zinc(II) bromide, [Zn(C 18 H 12 N 6 )(H 2 O)]Br 2 , and aqua[2,4,6-tris(pyridin-4-yl)-1,3,5-triazine]zinc(II) chloride, [Zn(C 18 H 12 N 6 )(H 2 O)]Cl 2 , were encountered. Structures in the orthorhombic space group Pnma (No. 62) for the bromide congener at 299 K and the chloride congener at 100 K were obtained. A phase transition for the bromide congener occurred upon cooling from 299 to 100 K, yielding a crystal polymorph with four domains that exhibits monoclinic P2 1 /m space-group symmetry (No. 11), which arises from conformational changes. The main intramolecular contacts that contribute to the crystal packing in all observed structures are H...H, Halide...H/H...Halide, C...H/H...C, and N...H/H...N. Intramolecular hydrogen bonding between the Zn-bound water and non-Zn-bound pyridyl N atoms is a prominent feature within the three-dimensional networks. Aromatic π-stacking between the non-Zn-bound pyridine rings and contacts involving the halide ligands further stabilize the crystal packing.

The activation of C-C bonds by transition-metal complexes is of continuing interest and acetonitrile (MeCN) has attracted attention as a cyanide source with comparatively low toxicity for organic cyanation reactions. A diiron end-on μ-η 1 :η 1 -CN-bridged complex was obtained from a crystallization experiment of an open-chain iron-NHC complex, namely, μ-cyanido-κ 2 C:N-bis{[(acetonitrile-κN)[3,3'-bis(pyridin-2-yl)-1,1'-(methylidene)bis(benzimidazol-2-ylidene)]iron(II)} tris(hexafluorophosphate), [Fe 2 (CN)(C 2 H 3 N) 2 (C 25 H 18 N 6 ) 2 ](PF 6 ) 3 . The cyanide appears to originate from the MeCN solvent by C-C bond cleavage or through carbon-hydrogen oxidation., (open access.)

Inhibition of LSD1 was proposed as promising and attractive therapies for treating osteoporosis. Here, we synthesized a series of novel TCP-(MP)-Caffeic acid analogs as potential LSD1 inhibitors to assess their inhibitory effects on osteoclastogenesis by using TRAP-staining assay and try to explore the preliminary SAR. Among them, TCP-MP-CA (11a) demonstrated osteoclastic bone loss both in vitro and in vivo, showing a significant improvement in the in vivo effects compared to the LSD1 inhibitor GSK-LSD1. Additionally, we elucidated a mechanism that 11a and its precursor that 11e directly bind to LSD1/CoREST complex through FAD to inhibit LSD1 demethylation activity and influence its downstream IκB/NF-κB signaling pathway, and thus regulate osteoclastic bone loss. These findings suggested 11a or 11e as potential novel candidates for treating osteoclastic bone loss, and a concept for further development of TCP-(MP)-Caffeic acid analogs for therapeutic use in osteoporosis clinics., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

The reaction of titanium(IV) chloride with sodium hexafluoroisopropoxide, carried out in hexafluoroisopropanol, produces titanium(IV) hexafluoroisopropoxide, which is a liquid at room temperature. Recrystallization from coordinating solvents, such as acetonitrile or tetrahydrofuran, results in the formation of bis-solvate complexes. These compounds are of interest as possible Ziegler-Natta polymerization catalysts. The acetonitrile complex had been structurally characterized previously and adopts a distorted octahedral structure in which the nitrile ligands adopt a cis configuration, with nitrogen lone pairs coordinated to the metal. The low-melting tetrahydrofuran complex has not provided crystals suitable for single-crystal X-ray analysis. However, the structure of chloridotris(hexafluoroisopropoxido-κO)bis(tetrahydrofuran-κO)titanium(IV), [Ti(C 3 HF 6 O) 3 Cl(C 4 H 8 O) 2 ], has been obtained and adopts a distorted octahedral coordination geometry, with a facial arrangement of the alkoxide ligands and adjacent tetrahydrofuran ligands, coordinated by way of metal-oxygen polar coordinate interactions., (open access.)

It is well known that Hirshfeld surfaces provide an easy and straightforward way of analysing intermolecular interactions in the crystal environment. The use of atomic Hirshfeld surfaces has also demonstrated that such surfaces carry information related to chemical bonds which allow a deeper evaluation of the structures. Here we briefly summarize the approach of atomic Hirshfeld surfaces while further evaluating the kind of information that can be retrieved from them. We show that the analysis of the metal-centre Hirshfeld surfaces from structures refined via Hirshfeld Atom Refinement (HAR) allow accurate evaluation of contacts of type M...H, and that such contacts can be related to the overall shape of the surfaces. The compounds analysed were tetraaquabis(3-carboxypropionato)metal(II), [M(C 4 H 3 O 4 ) 2 (H 2 O) 4 ], for metal(II)/M = manganese/Mn, cobalt/Co, nickel/Ni and zinc/Zn. We also evaluate the sensitivity of the surfaces by an investigation of seemingly flat surfaces through analysis of the curvature functions in the direction of C-C bonds. The obtained values not only demonstrate variations in curvature but also show a correlation with the hybridization of the C atoms involved in the bond.

The incommensurately modulated structure of (2S,3S)-2-amino-3-hydroxy-3-methyl-4-phenoxybutanoic acid dihydrate (C 11 H 15 NO 4 ·2H 2 O or I·2H 2 O) is described in the (3+1)-dimensional superspace group P2 1 2 1 2 1 (0β0)000 (β = 0.357). The loss of the three-dimensional periodicity is ascribed to the occupational modulation of one positionally disordered solvent water molecule, where the two positions are related by a small translation [ca 0.666 (9) Å] and ∼168 (5)° rotation about one of its O-H bonds, with an average 0.624 (3):0.376 (3) occupancy ratio. The occupational modulation of this molecule arises due to the competition between the different hydrogen-bonding motifs associated with each position. The structure can be very well refined in the average approximation (all satellite reflections disregarded) in the space group P2 1 2 1 2 1 , with the water molecule refined as disordered over two positions in a 0.625 (16):0.375 (16) ratio. The refinement in the commensurate threefold supercell approximation in the space group P112 1 is also of high quality, with the six corresponding water molecules exhibiting three different occupancy ratios averaging 0.635:0.365., (open access.)

Three structurally diverse 5-phenyltetrazolato (Tz) Ti, Zr, and Ta complexes, namely, (C 2 H 8 N)[Ti 2 (C 7 H 5 N 4 ) 5 (C 2 H 6 N) 4 ]·1.45C 6 H 6 or (Me 2 NH 2 )[Ti 2 (NMe 2 ) 4 (2,3-μ-Tz) 3 (2-η 1 -Tz) 2 ]·1.45C 6 H 6 , (1·1.45C 6 H 6 ), [Zr 2 (C 7 H 5 N 4 ) 6 (C 2 H 6 N) 2 (C 2 H 7 N) 2 ]·1.12C 6 H 6 ·0.382CH 2 Cl 2 or [Zr 2 (Me 2 NH) 2 (NMe 2 ) 2 (2,3-μ-Tz) 3 (2-η 1 -Tz) 2 (1,2-η 2 -Tz)]·1.12C 6 H 6 ·0.38CH 2 Cl 2 (2·1.12C 6 H 6 ·0.38CH 2 Cl 2 ), and (C 2 H 8 N) 2 [Ta 2 (C 7 H 5 N 4 ) 8 (C 2 H 6 N) 2 O]·0.25C 7 H 8 or (Me 2 NH 2 ) 2 [Ta 2 (NMe 2 ) 2 (2,3-μ-Tz) 2 (2-η 1 -Tz) 6 O]·0.25C 7 H 8 (3·0.25C 7 H 8 ), where TzH is 5-phenyl-1H-tetrazole, have been synthesized and structurally characterized. All three complexes are dinuclear; the Ti center in 1 is six-coordinate, whereas the Zr and Ta atoms in 2 and 3 are seven-coordinate. The coordination environments of the Ti centers in 1 are similar, and so are the ligations of the Ta centers in 3. In contrast, the two Zr centers in 2 bear a different number of ligands, one of which is a bidentate η 2 -5-phenyltetrazolato ligand that has not been observed previously for d-block elements. The dimethylamido ligand, present in the starting materials, remained unchanged, or was converted to dimethylamine and dimethylammonium during the synthesis. Dimethylamine coordinates as a neutral ligand, whereas dimethylammonium is retained as a hydrogen-bonded entity bridging Tz ligands., (open access.)

The VWA domain commonly functions as a crucial component of multiprotein complexes, facilitating protein-protein interactions. However, limited studies have focused on the systemic study of VWA proteins in plants. Here, we identified 28 VWA protein genes in Arabidopsis thaliana, categorized into three clades, with one tandem duplication event and four paralogous genes within collinearity blocks. Then, we determined their expression patterns under abiotic stresses by transcriptomic analysis. All five RGLG genes were found to be responsive to at least one kind of abiotic stress, and RGLG5 was identified as a multiple stress-responsive gene, coding an E3 ubiquitin ligase with a VWA domain and a C-terminal RING domain. Subsequently, we explored tolerant function of RGLG5 by determining the crystal structure of its VWA domain. The structural comparison revealed the allosteric regulation mechanism of RGLG5-VWA, wherein the deflection of α7 led to displacement of key residue binding metal ion within MIDAS motif. Our findings provide full-scale knowledge on VWA proteins, and insights into tolerant function of RGLG5-VWA in terms of crystal structure., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Masson SAS.)

Dicarbonyl[10,10-dimethyl-5,15-bis(pentafluorophenyl)biladiene]ruthenium(II), [Ru(C 33 H 16 F 10 N 4 )(CO) 2 ] or Ru(CO) 2 [DMBil1], is the first reported ruthenium(II) cis-dicarbonyl tetrapyrrole complex. The neutral complex sports two carbonyls and an oligotetrapyrrolic biladiene ligand. Notably, the biladiene adopts a coordination geometry that is well distorted from square planar and much more closely approximates a seesaw arrangement. Accordingly, Ru(CO) 2 [DMBil1] is not only the first ruthenium cis-dicarbonyl with a tetrapyrrole ligand, but also the first metal biladiene complex in which the tetrapyrrole does not adopt a (pseudo-)square-planar coordination geometry. Ru(CO) 2 [DMBil1] is weakly luminescent, displaying λ em  = 552 nm upon excitation at λ ex  = 500 nm, supports two reversible 1 e - reductions at -1.45 and -1.73 V (versus Fc + /Fc), and has significant absorption features at 481 and 531 nm, suggesting suitability for photocatalytic and photosensitization applications. While the structure of Ru(CO) 2 [DMBil1] was initially determined by X-ray diffraction, a traditionally acceptable quality structure could not be obtained (despite multiple attempts) because of consistently poor crystal quality. An independent structure obtained from electron diffraction experiments corroborates the structure of this unusual biladiene complex.

The crystal structures of two coordination compounds, (acetato-κO)(2,2'-bipyridine-κ 2 N,N')(1,10-phenanthroline-κ 2 N,N')copper(II) acetate hexahydrate, [Cu(C 2 H 3 O 2 )(C 10 H 8 N 2 )(C 12 H 8 N 2 )](C 2 H 3 O 2 )·6H 2 O or [Cu(bipy)(phen)Ac]Ac·6H 2 O, and (acetato-κO)bis(2,2'-bipyridine-κ 2 N,N')copper(II) acetate-acetic acid-water (1/1/3), [Cu(C 2 H 3 O 2 )(C 10 H 8 N 2 ) 2 ](C 2 H 3 O 2 )·C 2 H 4 O 2 ·3H 2 O or [Cu(bipy) 2 Ac]Ac·HAc·3H 2 O, are reported and compared with the previously published structure of [Cu(phen) 2 Ac]Ac·7H 2 O (phen is 1,10-phenanthroline, bipy for 2,2'-bipyridine, ac is acetate and Hac is acetic acid). The geometry around the metal centre is pentacoordinated, but highly distorted in all three cases. The coordination number and the geometric distortion are both discussed in detail, and all complexes belong to the space group P-1. The analysis of the geometric parameters and the Hirshfeld surface properties d norm and curvedness provide information about the metal-ligand interactions in these complexes and allow comparison with similar systems.

Aiming at confirming the chemical structure, herein, we report the crystal structure of Arbortristoside-A, isolated from the seeds of Nyctanthes arbor-tristis Linn. and investigated by single crystal X-ray crystallographic analysis. The unambiguously established structure of Arbortristoside-A not only addresses previously reported structural flaws but also encourages its chemical, computational, and physiological studies as a lead drug candidate of pharmaceutical significance.

Luminescent Cu I complexes are an important class of coordination compounds due to their relative abundance, low cost and ability to display excellent luminescence. The title Cu 2 I 2 P 2 S 2 -type binuclear complex, di-μ-iodido-bis[(thiourea-κS)(triphenylphosphine-κP)copper(I)], [Cu 2 I 2 (CH 4 N 2 S) 2 (C 18 H 15 P) 2 ], conventionally abbreviated as Cu 2 I 2 TPP 2 TU 2 , where TPP and TU represent triphenylphosphine and thiourea, respectively, is described. In this complex, each Cu I atom adopts a CuI 2 PS four-coordination mode and pairs of atoms are connected to each other by two μ 2 -I ligands to form a centrosymmetric binuclear cluster. It was also found that the paper-based film of this complex exhibited obvious luminescence light-up sensing for pyridine and 4-methylpyridine.

Osteosarcoma (OS) is the most common malignant primary bone tumor in humans and occurs in various subtypes. Tumor formation happens through malignant osteoblasts producing immature bone. In the present paper we studied two different subtypes of osteosarcoma, from one individual with conventional OS with massive sclerosis and one individual with parosteal OS, based on a multimodal approach including small angle x-ray scattering (SAXS), wide angle x-ray diffraction (WAXS), backscattered electron imaging (BEI) and Raman spectroscopy. It was found that both tumors showed reduced mineral particle sizes and degree of orientation of the collagen-mineral composite in the affected areas, alongside with a decreased crystallinity. Distinct differences between the tumor material from the two individuals were found in the degree of mineralization. Further differences were observed in the carbonate to phosphate ratio, which is related to the degree of carbonate substitution in bone mineral and indicative of the turnover rate. The contraction of the c-axis of the bone mineral crystals proved to be a further, very sensitive parameter, potentially indicative of malignancy., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Herein we report the crystal structures of two benzodiazepines obtained by reacting N,N'-(4,5-diamino-1,2-phenylene)bis(4-methylbenzenesulfonamide) (1) or 4,5-(4-methylbenzenesulfonamido)benzene-1,2-diaminium dichloride (1·2HCl) with acetone, giving 2,2,4-trimethyl-8,9-bis(4-methylbenzenesulfonamido)-2,3-dihydro-5H-1,5-benzodiazepine, C 26 H 30 N 4 O 4 S 2 (2), and 2,2,4-trimethyl-8,9-bis(4-methylbenzenesulfonamido)-2,3-dihydro-5H-1,5-benzodiazepin-1-ium chloride 0.3-hydrate, C 26 H 31 N 4 O 4 S 2 + ·Cl - O (3). Compounds 2 and 3 were first obtained in attempts to recrystallize 1 and 1·2HCl using acetone as solvent. This solvent reacted with the vicinal diamines present in the molecular structures, forming a 5H-1,5-benzodiazepine ring. In the crystal structure of 2, the seven-membered ring of benzodiazepine adopts a boat-like conformation, while upon protonation, observed in the crystal structure of 3, it adopts an envelope-like conformation. In both crystalline compounds, the tosylamide N atoms are not in resonance with the arene ring, mainly due to hydrogen bonds and steric hindrance caused by the large vicinal groups in the aromatic ring. At a supramolecular level, the crystal structure is maintained by a combination of hydrogen bonds and hydrophobic interactions. In 2, amine-to-tosyl N-H...O and amide-to-imine N-H...N hydrogen bonds can be observed. In contrast, in 3, the chloride counter-ion and water molecule result in most of the hydrogen bonds being of the amide-to-chloride and ammonium-to-chloride N-H...Cl types, while the amine interacts with the tosyl group, as seen in 2. In conclusion, we report the synthesis of 1, 1·2HCl and 2, as well as their chemical characterization. For 2, two synthetic methods are described, i.e. solvent-mediated crystallization and synthesis via a more efficient and cleaner route as a polycrystalline material. Salt 3 was only obtained as presented, with only a few crystals being formed.2 O (3). Compounds 2 and 3 were first obtained in attempts to recrystallize 1 and 1·2HCl using acetone as solvent. This solvent reacted with the vicinal diamines present in the molecular structures, forming a 5H-1,5-benzodiazepine ring. In the crystal structure of 2, the seven-membered ring of benzodiazepine adopts a boat-like conformation, while upon protonation, observed in the crystal structure of 3, it adopts an envelope-like conformation. In both crystalline compounds, the tosylamide N atoms are not in resonance with the arene ring, mainly due to hydrogen bonds and steric hindrance caused by the large vicinal groups in the aromatic ring. At a supramolecular level, the crystal structure is maintained by a combination of hydrogen bonds and hydrophobic interactions. In 2, amine-to-tosyl N-H...O and amide-to-imine N-H...N hydrogen bonds can be observed. In contrast, in 3, the chloride counter-ion and water molecule result in most of the hydrogen bonds being of the amide-to-chloride and ammonium-to-chloride N-H...Cl types, while the amine interacts with the tosyl group, as seen in 2. In conclusion, we report the synthesis of 1, 1·2HCl and 2, as well as their chemical characterization. For 2, two synthetic methods are described, i.e. solvent-mediated crystallization and synthesis via a more efficient and cleaner route as a polycrystalline material. Salt 3 was only obtained as presented, with only a few crystals being formed.

The structures of a series of 2:1 cocrystals formed between 4-(dimethylamino)pyridine and each of 1,2,4,5-tetrachloro-3,6-diiodobenzene, 2C 7 H 10 N 2 ·C 6 Cl 4 I 2 , 1,2,4,5-tetrabromo-3,6-diiodobenzene, 2C 7 H 10 N 2 ·C 6 Br 4 I 2 , 1-bromo-4-iodo-2,3,5,6-tetrafluorobenzene, 2C 7 H 10 N 2 ·C 6 BrF 4 I, and 1,2-dibromo-4,5-difluoro-3,6-diiodobenzene, 2C 7 H 10 N 2 ·C 6 Br 2 F 2 I 2 , are reported. In all five structures, the core halogen-bonded 2:1 trimolecular units have geometrically similar parameters, with the central halogen-bond donor flanked by two pyridine halogen-bond acceptors twisted with respect to the central halogen-bond donor at angles ranging from 76 to 86°. The I...N halogen-bond separations are all short, ranging from 73.3 to 76.7% of the sum of the van der Waals radii, while the C-I...N bond angles are essentially linear. The Br...N halogen-bond separation in the cocrystal formed with 1-bromo-4-iodo-2,3,5,6-tetrafluorobenzene is 80.4% of the sum of the van der Waals radii. Subtle differences in the crystal packings are attributed to the role of secondary C-H...π and weak π-type interactions with chloro and bromo substituents. The cocrystals 2C 7 H 10 N 2 ·C 6 Cl 4 I 2 and 2C 7 H 10 N 2 ·C 6 Br 4 I 2 are isomorphous.

Treating the amide acetanilide (N-phenylacetamide, C 8 H 9 NO) with aqueous strong acids allowed the structures of five hemi-protonated salt forms of acetanilide to be elucidated. N-(1-Hydroxyethylidene)anilinium chloride-N-phenylacetamide (1/1), [(C 8 H 9 NO) 2 H][Cl], and the bromide, [(C 8 H 9 NO) 2 H][Br], triiodide, [(C 8 H 9 NO) 2 H][I 3 ], tetrafluoroborate, [(C 8 H 9 NO) 2 H][BF 4 ], and diiodobromide hemi(diiodine), [(C 8 H 9 NO) 2 H][I 2 Br]·0.5I 2 , analogues all feature centrosymmetric dimeric units linked by O-H...O hydrogen bonds that extend into one-dimensional hydrogen-bonded chains through N-H...X interactions, where X is the halide atom of the anion. Protonation occurs at the amide O atom and results in systematic lengthening of the C=O bond and a corresponding shortening of the C-N bond. The size of these geometric changes is similar to those found for hemi-protonated paracetamol structures, but less than those in fully protonated paracetamol structures. The bond angles of the amide fragments are also found to change on protonation, but these angular changes are also influenced by conformation, namely, whether the amide group is coplanar with the phenyl ring or twisted out of plane., (open access.)

Three 2,4-diarylpyrroles were synthesized starting from 4-nitrobutanones and the crystal structures of two derivatives were analysed. These are 4-(4-methoxyphenyl)-2-(thiophen-2-yl)-1H-pyrrole, C 15 H 13 NOS, and 3-(4-bromophenyl)-2-nitroso-5-phenyl-1H-pyrrole, C 16 H 11 BrN 2 O. Although pyrroles without substituents at the α-position with respect to the N atom are very air sensitive and tend to polymerize, we succeeded in growing an adequate crystal for X-ray diffraction analysis. Further derivatization using sodium nitrite afforded a nitrosyl pyrrole derivative, which crystallized in the triclinic space group P-1 with Z = 6. Thus, herein we report the first crystal structure of a nitrosyl pyrrole. Interestingly, the co-operative hydrogen bonds in this NO-substituted pyrrole lead to a trimeric structure with bifurcated halogen bonds at the ends, forming a two-dimensional (2D) layer with interstitial voids having a radius of 5 Å, similar to some reported macrocyclic porphyrins.

Main proteases (M pro s) are a class of conserved cysteine hydrolases among coronaviruses and play a crucial role in viral replication. Therefore, M pro s are ideal targets for the development of pan-coronavirus drugs. X77, previously developed against SARS-CoV M pro , was repurposed as a non-covalent tight binder inhibitor against SARS-CoV-2 M pro during COVID-19 pandemic. Many novel inhibitors with favorable efficacy have been discovered using X77 as a reference, suggesting that X77 could be a valuable scaffold for drug design. However, the broad-spectrum performance of X77 and underlying mechanism remain less understood. Here, we reported the crystal structures of M pro s from SARS-CoV-2, SARS-CoV, and MERS-CoV, and several M pro mutants from SARS-CoV-2 variants bound to X77. A detailed analysis of these structures revealed key structural determinants essential for interaction and elucidated the binding modes of X77 with different coronaviral M pro s. The potencies of X77 against these investigated M pro s were further evaluated through molecular dynamic simulation and binding free energy calculation. These data provide molecular insights into broad-spectrum inhibition against coronaviral M pro s by X77 and the similarities and differences of X77 when bound to various M pro s, which will promote X77-based design of novel antivirals with broad-spectrum efficacy against different coronaviruses and SARS-CoV-2 variants., Competing Interests: Declaration of competing interest The authors declare that there is no conflicts of interests., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Pyrone-2,4-dicarboxylic acid (PDC) is a valuable polymer precursor that can be derived from the microbial degradation of lignin. The key enzyme in the microbial production of PDC is CHMS dehydrogenase, which acts on the substrate 4-carboxy-2-hydroxymuconate-6-semialdehyde (CHMS). We present the crystal structure of CHMS dehydrogenase (PmdC from Comamonas testosteroni) bound to the cofactor NADP, shedding light on its three-dimensional architecture, and revealing residues responsible for binding NADP. Using a combination of structural homology, molecular docking, and quantum chemistry calculations we have predicted the binding site of CHMS. Key histidine residues in a conserved sequence are identified as crucial for binding the hydroxyl group of CHMS and facilitating dehydrogenation with NADP. Mutating these histidine residues results in a loss of enzyme activity, leading to a proposed model for the enzyme's mechanism. These findings are expected to help guide efforts in protein and metabolic engineering to enhance PDC yields in biological routes to polymer feedstock synthesis., Competing Interests: Conflict of interest The authors declare that they have no conflicts of interest with the contents of this article., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

The title compound, bis-[μ-2,2'-(4 H -1,2,4-triazole-3,5-di-yl)di-acetato]-bis-[di-aqua-copper(II)] dihydrate, [Cu 2 (C 6 H 5 N 3 O 4 ) 2 (H 2 O) 4 ]·2H 2 O, is a dinuclear octa-hedral Cu II triazole-based complex. The central copper atoms are hexa-coordinated by two nitro-gen atoms in the equatorial positions, two equatorial oxygen atoms of two carboxyl-ate substituents in position 3 and 5 of the 1,2,4-triazole ring, and two axial oxygen atoms of two water mol-ecules. Two additional solvent water mol-ecules are linked to the title mol-ecule by O-H⋯N and O⋯H-O hydrogen bonds. The crystal structure is built up from the parallel packing of discrete supra-molecular chains running along the a -axis direction. Hirshfeld surface analysis suggests that the most important contributions to the surface contacts are from H⋯O/O⋯H (53.5%), H⋯H (28.1%), O⋯O (6.3%) and H⋯C/C⋯H (6.2%) inter-actions. The crystal studied was twinned by a twofold rotation around [100]., (© Vynohradov et al. 2024.)

In the title compound, C 33 H 29 ClN 2 O 2 , the two piperidine rings of the di-aza-bicyclo moiety adopt distorted-chair conformations. Inter-molecular C-H⋯π inter-actions are mainly responsible for the crystal packing. The inter-molecular inter-actions were qu-anti-fied and analysed using Hirshfeld surface analysis, revealing that H⋯H inter-actions contribute most to the crystal packing (52.3%). The mol-ecular structure was further optimized by density functional theory (DFT) at the B3LYP/6-31 G(d,p) level and is compared with the experimentally determined mol-ecular structure in the solid state., (© Divyabharathi et al. 2024.)

In the structure of the title salt, {[Ba(μ 3 -C 3 H 2 N 3 O 2 ) 2 (μ-H 2 O)(H 2 O)]·H 2 O} n , the barium ion and all three oxygen atoms of the water mol-ecules reside on a mirror plane. The hydrogen atoms of the bridging water and the solvate water mol-ecules are arranged across a mirror plane whereas all atoms of the monodentate aqua ligand are situated on this mirror plane. The distorted ninefold coord-ination of the Ba ions is completed with four nitroso-, two carbonyl- and three aqua-O atoms at the distances of 2.763 (3)-2.961 (4) Å and it is best described as tricapped trigonal prism. The three-dimensional framework structure is formed by face-sharing of the trigonal prisms, via μ-nitroso- and μ-aqua-O atoms, and also by the bridging coordination of the anions via carbonyl-O atoms occupying two out of the three cap positions. The solvate water mol-ecules populate the crystal channels and facilitate a set of four directional hydrogen bonds. The principal Ba-carbamoyl-cyano-nitro-somethanido linkage reveals a rare example of the inherently polar binodal six- and three-coordinated bipartite topology (three-letter notation sit ). It suggests that small resonance-stabilized cyano-nitroso anions can be utilized as bridging ligands for the supra-molecular synthesis of MOF solids. Such an outcome may be anti-cipated for a broader range of hard Lewis acidic alkaline earth metal ions, which perfectly match the coordination preferences of highly nucleophilic nitroso-O atoms. Thermal analysis reveals two-stage dehydration of the title compound (383 and 473 K) followed by decomposition with release of CO 2 , HCN and H 2 O at 558 K., (© Domasevitch et al. 2024.)

This study presents the synthesis, characterization and Hirshfeld surface analysis of 1-[6-bromo-2-(3-bromo-phen-yl)-1,2,3,4-tetra-hydro-quinolin-4-yl]pyrrolidin-2-one, C 19 H 18 Br 2 N 2 O. In the title compound, the pyrrolidine ring adopts a distorted envelope configuration. In the crystal, mol-ecules are linked by inter-molecular N-H⋯O, C-H⋯O and C-H⋯Br hydrogen bonds, forming a three-dimensional network. In addition, pairs of mol-ecules along the c axis are connected by C-H⋯π inter-actions. According to a Hirshfeld surface study, H⋯H (36.9%), Br⋯H/H⋯Br (28.2%) and C⋯H/H⋯C (24.3%) inter-actions are the most significant contributors to the crystal packing., (© Pronina et al. 2024.)

Propane-1,3-diaminium squarate dihydrate, C 3 H 12 N 2 2+ ·C 4 O 4 2- ·2H 2 O, results from the proton-transfer reaction of propane-1,3-di-amine with squaric acid and subsequent crystallization from aqueous medium. The title compound crystallizes in the tetra-gonal crystal system (space group P 4 bm ) with Z = 2. The squarate dianion belongs to the point group D 4 h 2 site symmetry. The orientation of the propane-1,3-diaminium ions makes the crystal structure polar in the C 2 v -symmetric all- anti conformation and resides on a special position with mm 2 site symmetry. The orientation of the propane-1,3-diaminium ions makes the crystal structure polar in the c- axis direction. The solid-state supra-molecular structure features a triperiodic network of strong hydrogen bonds of the N-H⋯O and O-H⋯O types., (© Seidel and Kolev 2024.)

The mol-ecular structure of the tripodal carbamoyl-methyl-phosphine oxide compound diethyl {[(5-[2-(di-eth-oxy-phosphor-yl)acetamido]-3-{2-[2-(di-eth-oxy-phos-phor-yl)acetamido]-eth-yl}pent-yl)carbamo-yl]meth-yl}phospho-nate, C 25 H 52 N 3 O 12 P 3 , features six intra-molecular hydrogen-bonding inter-actions. The phospho-nate groups have key bond lengths ranging from 1.4696 (12) to 1.4729 (12) Å (P=O), 1.5681 (11) to 1.5811 (12) Å (P-O) and 1.7881 (16) to 1.7936 (16) Å (P-C). Each amide group adopts a nearly perfect trans geometry, and the geometry around each phophorus atom resembles a slightly distorted tetra-hedron., (© Wackerle et al. 2024.)

The title structure, {[Cu(C 4 H 11 NO) 3 ][Cu 4 (CN) 6 ]·[Cu(C 4 H 10 NO) 2 (H 2 O)]·H 2 O} n , is made up of diperiodic honeycomb Cu I CN networks built from [Cu 4 (CN) 6 ] 2- units, together with two independent Cu II complexes: six-coord-inate [Cu(CH 3 CH 2 CH(NH 2 )CH 2 OH) 3 ] 2+ cations, and five-coordinate [Cu(CH 3 CH 2 CH(NH 2 )CH 2 O) 2 ·H 2 O] neutral species. The two Cu II complexes are not covalently bonded to the Cu I CN networks. Strong O-H⋯O hydrogen bonds link the Cu II complexes into pairs and the pairs are hydrogen bonded into chains along the crystallographic b axis via the hydrate water mol-ecule. In addition, O-H⋯(CN) and N-H⋯(CN) hydrogen bonds link the cations to the CuCN network. In the honeycomb polymeric moiety, all bridging cyanido ligands are disordered over two orientations, head-to-tail and tail-to-head, with occupancies for C and N atoms varying for each CN group., (© Corfield and Salvi 2024.)

The title compound (systematic name: pyridinium 4-methyl-benzene-sulfonate), C 5 H 6 N + ·C 7 H 7 O 3 S - , is the pyridinium salt of para -toluene-sulfonic acid. In the crystal, classical N-H⋯O hydrogen bonds as well as C-H⋯O contacts connect the cationic and anionic entities into sheets lying parallel to the ab plane., (© Hosten and Betz 2024.)

The title compound, [Ni 2 (C 8 H 6 N 3 ) 2 (C 2 H 3 O 2 ) 2 (C 5 H 8 N 2 ) 2 ] or [Ni( μ -OOCCH 3 )(2-PyPz)(Me 2 PzH)] 2 ( 1 ) [2-PyPz = 3-(pyridin-2-yl) pyrazole; Me 2 PzH = 3,5-dimethyl pyrazole] was synthesized from Ni(OOCCH 3 ) 2 ·4H 2 O, 2-PyPzH, Me 2 PzH and tri-ethyl-amine as a base. Compound 1 {[Ni 2 (C 30 H 34 N 10 Ni 2 O 4 )]} at 100 K has monoclinic ( P 2 1 / n ) symmetry and the mol-ecules have crystallographic inversion symmetry. Mol-ecules of 1 comprise an almost planar dinuclear Ni II core with an N 4 O 2 coordination environment. The equatorial plane consists of N 3 ,O coordination derived from one of the bidentate acetate O atoms and three of the N atoms of the chelating 2-PyPz ligand while the axial positions are occupied by neutral Me 2 PzH and the second O atom of the acetate unit. The Ni atoms are bridged by the nitro-gen atom of a deprotonated 2-PyPz ligand. Compound 1 exhibits various inter- and intra-molecular C-H⋯O and N-H⋯O hydrogen bonds., (© Pilavadi et al. 2024.)

In the title salt [systematic name: 4-(3-carb-oxy-1-ethyl-6-fluoro-4-oxo-1,4-di-hydro-quin-olin-7-yl)piperazin-1-ium nitrate], C 16 H 19 FN 3 O 3 + ·NO 3 - , proton transfer from nitric acid to the N atom of the piperazine ring of norfloxacin has occurred to form a mol-ecular salt. In the extended structure, N-H⋯O hydrogen bonds link alternating cations and anions into [100] chains, which are reinforced by aromatic π-π stacking inter-actions between the quinoline moieties of the norfloxacinium cations., (© Rasulov et al. 2024.)

In the hydrated title salt, (C 10 H 8 NO 2 ) 2 [SnCl 6 ]·2H 2 O, the tin(IV) atom is located about a center of inversion. In the crystal structure, the organic cation, the octa-hedral inorganic anion and the water mol-ecule of crystallization inter-act through O-H⋯O, N-H⋯O and O-H⋯Cl hydrogen bonds, supplemented by weak π-π stacking between neighboring cations, and C-Cl⋯π inter-actions., (© Benhamada et al. 2024.)

The accumulation of photosensitizers (PSs) in lesion sites but not in other organs is an important challenge for efficient image guiding in photodynamic therapy. Cancer cells are known to express a significant number of albumin-binding proteins that take up albumin as a nutrient source. Here, we converted albumin to a novel BODIPY-like PS by generating a tetrahedral boron environment via a flick reaction. The formed albumin PS has almost the same 3-dimensional structural feature as free albumin because binding occurs at Sudlow Site 1, which is located in the interior space of albumin. An i.v. injection experiment in tumor-bearing mice demonstrated that the human serum albumin PS effectively accumulated in cancer tissue and, more surprisingly, albumin PS accumulated much more in the cancer tissue than in the liver and kidneys. The albumin PS was effective at killing tumor cells through the generation of reactive oxygen species under light irradiation. The crystal structure of the albumin PS was fully elucidated by X-ray crystallography; thus, further tuning of the structure will lead to novel physicochemical properties of the albumin PS, suggesting its potential in biological and clinical applications., Competing Interests: Declaration of competing interest The authors declare no competing financial interest., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Akkermansia muciniphila is a mucin-degrading probiotic that colonizes the gastrointestinal tract. Genomic analysis identified a set of genes involved in the biosynthesis of corrin ring, including the cobalt factor II methyltransferase CbiL, in some phylogroups of A. muciniphila, implying a potential capacity for de novo synthesis of cobalamin. In this work, we determined the crystal structure of CbiL from A. muciniphila at 2.3 Å resolution. AmCbiL exists as a dimer both in solution and in crystal, and each protomer consists of two α/β domains, the N-terminal domain and the C-terminal domain, consistent with the folding of typical class III MTases. The two domains create an open trough, potentially available to bind the substrates SAM and cobalt factor II. Sequence and structural comparisons with other CbiLs, assisted by computer modeling, suggest that AmCbiL should have cobalt factor II C-20 methyltransferase activity. Our results support that certain strains of A. muciniphila may be capable of synthesizing cobalamin de novo., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

As a response to viral infections, bacteria have evolved the CRISPR-Cas system as an adaptive immune mechanism, enabling them to target and eliminate viral genetic material introduced during infection. However, viruses have also evolved mechanisms to counteract this bacterial defense, including anti-CRISPR proteins, which can inactivate the CRISPR-Cas adaptive immune system, thus aiding the viruses in their survival and replication within bacterial hosts. In this study, we establish the high-resolution crystal structure of the Type IE anti-CRISPR protein, AcrIE3. Our structural examination showed that AcrIE3 adopts a helical bundle fold comprising four α-helices, with a notably extended loop at the N-terminus. Additionally, surface analysis of AcrIE3 revealed the presence of three acidic regions, which potentially play a crucial role in the inhibitory function of this protein. The structural information we have elucidated for AcrIE3 will provide crucial insights into fully understanding its inhibitory mechanism. Furthermore, this information is anticipated to be important for the application of the AcrIE family in genetic editing, paving the way for advancements in gene editing technologies., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Iron-sulfur (Fe-S) clusters are ubiquitous and are necessary to sustain basic life processes. The intracellular Fe-S clusters do not form spontaneously and many proteins are required for their biosynthesis and delivery. The bacterial P-loop NTPase family protein ApbC participates in Fe-S cluster assembly and transfers the cluster into apoproteins, with the Walker A motif and CxxC motif being essential for functionality of ApbC in Fe-S protein biogenesis. However, the structural basis underlying the ApbC activity and the motifs' role remains unclear. Here, we report the crystal structure of Escherichia coli ApbC at 2.8 Å resolution. The dimeric structure is in a W shape and the active site is located in the 2-fold center. The function of the motifs can be annotated by structural analyses. ApbC has an additional N-terminal domain that differs from other P-loop NTPases, possibly conferring its inherent specificity in vivo., Competing Interests: Declaration of competing interest We declare that we have no financial and personal relationships with other people or organizations that can inappropriately influence our work, there is no professional or other personal interest of any nature or kind in any product, service and/or company that could be construed as influencing the position presented in, or the review of, the manuscript entitled., (Copyright © 2024 Elsevier Inc. All rights reserved.)