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C60H51N16O16Cl3Co2, monoclinic, P21/ n (no. 14), a = 35.652(4) Å, b = 14.1314(16) Å, c = 25.141(3) Å, β = 105.113(2)°, V = 12228(3) Å3, Z = 8, Rgt( F) = 0.0651, wRref( F2) = 0.1663, T = 103(2) K. [ABSTRACT FROM AUTHOR]

Membrane proteins play key roles in many fundamental functions in cells including ATP synthesis, ion and molecule transporter, cell signalling and enzymatic reactions, accounting for ~30% genes of whole genomes. However, the hydrophobic nature of membrane proteins frequently hampers the progress of structure determination. Detergent screening is the critical step in obtaining stable detergent-solubilized membrane proteins and well-diffracting protein crystals. Fluorescence Detection Size Exclusion Chromatography (FSEC) has been developed to monitor the extraction efficiency and monodispersity of membrane proteins in detergent micelles. By tracing the FSEC profiles of GFP-fused membrane proteins, this method significantly enhances the throughput of detergent screening. However, current methods to acquire FSEC profiles require either an in-line fluorescence detector with the SEC equipment or an off-line spectrofluorometer microplate reader. Here, we introduce an alternative method detecting the absorption of GFP (FA-SEC) at 485 nm, thus making this methodology possible on conventional SEC equipment through the in-line absorbance spectrometer. The results demonstrate that absorption is in great correlation with fluorescence of GFP. The comparably weaker absorption signal can be improved by using a longer path-length flow cell. The FA-SEC profiles were congruent with the ones plotted by FSEC, suggesting FA-SEC could be a comparable and economical setup for detergent screening of membrane proteins. [ABSTRACT FROM AUTHOR]

Motivation: A series of Eu2+ (0.0025≤ × ≤0.025) activated Sr2SiO4:xEu2+ (SSO:xEu2+) phosphors were synthesized via a sol-gel method. The phosphors were characterized by x-ray diffraction (XRD), scanning electron microscopy (SEM) and photoluminescence (PL) spectroscopy. The differences between α' and β phase of SSO in the density of states and energy band gap were investigated. Results: The energy gap of α'-SSO and β-SSO are 4.489 and 4.106 eV, respectively. While, two samples showed similar total and partial densities of states. Under the excitation by the ultra violet (UV) light (365 nm), the SSO: xEu2+ phosphor exhibited a green emission band from 400 to 700 nm, which was corresponding to the transition of 5d → 4f of Eu2+ ions. Two emission peaks at 464 and 532 nm could be obtained through Gauss fitting curves. The ratio of the blue to green emission peak decreased with the Eu2+ concentration and the peaks shifted regularly with it. The thermal quenching property was investigated and its activation energy was calculated. The results indicated that this phosphor could be a candidate of green phosphor for UV-based light-emitting diodes (LEDs). [ABSTRACT FROM AUTHOR]

C26H42N4O15Ni, triclinic, P1̅ (no. 2), a = 6.9662(8) Å, b = 9.0381(10) Å, c = 13.4863(15) Å, α = 71.430(1)°, β = 79.568(1)°, γ = 85.621(1)°, V = 791.44(15) Å3, Z = 1, Rgt (F) = 0.0377, wRref (F2 ) = 0.1312, T = 293(2) K. [ABSTRACT FROM AUTHOR]

Two kinds of tetranuclear Zn(ii) molecular clusters with the designed aroylhydrazone Schiff base ligand (H3L), [Zn4(HL)4]·3(DMF)·3(H2O) (1) and [Zn4(HL)2(CH3COO)4]·2(DMF)·2(CH3OH) (2), have been synthesized and studied. Molecular cluster 1 displayed a Zn4O4 boat-shaped core and 2 presented a discrete linear tetranuclear Zn(ii) structure. The luminescent properties of the two molecular clusters have been investigated, which exhibit a wide range of photo-luminescence in different organic solvents. [ABSTRACT FROM AUTHOR]

A new coordination polymer, {[Ni2(CH3O-ip)2(1,6-bih)2]}n(1), (CH3O-H2ip = 5-methoxyisophthalic acid, 1,6-bih = 1,6-bis(imidazol-1-yl)hexane), has been obtained under hydrothermal conditions. Complex 1 was determined by single-crystal X-ray diffraction analysis and further characterized by elemental analysis and IR spectroscopy. Complex 1 shows a two-dimensional corrugated layer with (3,5)-connected (42.6)(42.67.8) topology. Furthermore, thermogravimetric property of 1 was also investigated. Supplemental materials are available for this article. Go to the publisher's online edition ofSynthesis and Reactivity in Inorganic, Metal-Organic, and Nano-Metal Chemistryto view the supplemental file. [ABSTRACT FROM AUTHOR]

A short and efficient route to synthesis of a series of N-dichloroacetyl diazabicyclo derivatives has been developed. The compounds were obtained by cycloaddition of levulinic acid or ester with diamine, followed by acylation with dichloroacetyl chloride. All products were characterized by IR, 1H NMR, 13C NMR, MS, and elemental analysis. The single crystal of compound 4c was determined by X-ray crystallographic analysis. All compounds were tested for their herbicide safeners activity of protecting maize from injury with acetochlor. [ABSTRACT FROM AUTHOR]

Abstract: Three new tridentate copper(II) complexes [Cu(dthp)Cl2] (1) (dthp=2,6-di(thiazol-2-yl)pyridine), [Cu(dmtp)Cl2] (2) (dmtp=2,6-di(5-methyl-4H-1,2,4-triazol-3-yl)pyridine) and [Cu(dtp)Cl2] (3) (dtp=2,6-di(4H-1,2,4-triazol-3-yl)pyridine) have been synthesized and characterized. Crystal structure of complex 1 shows that the complex existed as distorted square pyramid with five co-ordination sites occupied by the tridentate ligand and the two chlorine anions. Ethidium bromide displacement assay, viscosity measurements, circular dichroism studies and cyclic voltammetric experiments suggested that these complexes bound to DNA via an intercalative mode. Three Cu(II) complexes were found to efficiently cleave DNA in the presence of sodium ascorbate, and singlet oxygen (1O2) and hydrogen peroxide were proved to contribute to the DNA cleavage process. They exhibited anticancer activity against HeLa, Hep-G2 and BEL-7402 cell lines. Nuclear chromatin cleavage has also been observed with AO/EB staining assay and the alkaline single-cell gel electrophoresis (comet assay). The results demonstrated that three Cu(II) complexes cause DNA damage that can induce the apoptosis of BEL-7402 cells. [Copyright &y& Elsevier]

Trivalent terbium (Tb3+) doped double molybdate AGd(MoO4)2(A = Li+, Na+) phosphors have been synthesized by combustion reaction. The crystal structures and luminescent properties of the phosphors are investigated in this paper. The XRD patterns indicate that AGd(MoO4)2:Tb3+ phosphors take on single phase when the precursors are sintered at 700°C for 3 h. The average crystal size is about 2.0 μm. LiGd(MoO4)2:Tb3+ and NAGd(MoO4)2:Tb3+ phosphors have the similar luminescent properties. The influences of urea and Tb3+ concentration on the luminescent properties of phosphor samples are also discussed in detail. The results show that Tb3+ activated LiGd(MoO4)2 phosphors is a potential candidate for green phosphor in ultraviolet (UV) -based white LED. [ABSTRACT FROM AUTHOR]

A new coordination polymer, {[Cu(Brip)(1,4-btb)1.5]·2H2O}n, (H2Brip = 5-bromoisophthalic acid, 1,4-btb = 1,4-bis(triazol) butane) was prepared under hydrothermal condition by the reactions of Cu(II) acetate with H2Brip and 1,4-btb. The title complex was determined by single-crystal X-ray diffraction analysis and further characterized by elemental analysis and IR spectroscopy. Complex 1 has a 3D network extended by both H2Brip and 1,4-btb ligands that employ the same bis-monodentate bridging coordination modes. From the view of topology, the structure of 1 could be described as a 5-connected (44·66)-nov net. Two of such nets penetrate with each other to generate a 2-fold interpenetrating 3D network. In addition, the thermal stability of the title complex was briefly investigated. [ABSTRACT FROM AUTHOR]

The article discusses the crystal structure of poly[(.3-4-(4-oxopyridin-1(4H)-yl)phtalato-κ4O,O':O'':O''')-(μ2-2-carboxy-5-(4-oxopyridin-1(4H)-yl)benzoato-κ3O,O':O'')samarium(III)]. Topics discussed include its physical properties, chemical formula, chemical structure, and its atomic coordinates and displacement parameters.

The topology of helix-bundle membrane proteins provides low-resolution structural information with regard to the number and orientation of membrane-spanning helices, as well as the sidedness of intra/extra-cellular domains. In the past decades, several strategies have been developed to experimentally determine the topology of membrane proteins. However, generally, these methods are labour-intensive, time-consuming and difficult to implement for quantitative analysis. Here, we report a novel approach, site-directed alkylation detected by in-gel fluorescence (SDAF), which monitors the fluorescent band shift caused by alkylation of the EGFP-fused target membrane protein bearing one single introduced cysteine. In-gel fluorescence provides a unique readout of target membrane proteins with EGFP fusion from non-purified samples, revealing a distinct 5 kDa shift on SDS-PAGE gel due to conjugation with mPEG-MAL-5K. Using the structurally characterised bile acid transporter ASBTNM as an example, we demonstrate that SDAF generates a topology map consistent with the crystal structure. The efficiency of mPEG-MAL-5K modification at each introduced cysteine can easily be quantified and analysed, providing a useful tool for probing the solvent accessibility at a specific position of the target membrane protein. [ABSTRACT FROM AUTHOR]

The article discusses the crystal structure of hexaaquazinc(II) bis(6-methyl-2-oxo-1,2- dihydroxopyridine-4-carboxylate, whose chemical formulae is C14H24N2O12Zn. Topics discussed include its physical properties, chemical formula, chemical structure, and its atomic coordinates and displacement parameters.

[Display omitted] • Two lanthanide − titanium oxo clusters EuTi 9 and TbTi 9 protected by four kinds of ligands were prepared. • The EuTi 9 and TbTi 9 cluster core containing ten metal ions shows pyramid-like structure. • EuTi 9 and TbTi 9 display the temperature-dependent luminescence properties. Two pyramid-like lanthanide − titanium − oxo clusters formulated as LnTi 9 (µ 2 -O) 5 (µ 3 -O) 7 (µ 3 -OH) 2 (O i Pr)(acac) 2 (TCA) 10 (THF) (LnTi 9 , Ln = Eu / Tb, HTCA = 2-thiophenecarboxylic acid) were prepared through the reaction of Ln(acac) 3 , 2-thiophenecarboxylic acid (HTCA), Ti(O i Pr) 4 and THF. The 10-nuclearity-metal-core [LnTi 9 (µ 2 -O) 5 (µ 3 -O) 7 (µ 3 -OH) 2 ]13+ is protected by four kinds of ligands. EuTi 9 and TbTi 9 exhibit characteristic emissions of Eu3+ / Tb3+ under ultraviolet excitation. The temperature-dependent luminescence results show EuTi 9 shows a good linear relationship between the luminescence intensity and temperature range of 80–320 K, while TbTi 9 has high temperature-sensitivity in different temperature ranges. [ABSTRACT FROM AUTHOR]

• The mechanism of conformational isomerization of ASBT NM remains undefined. • Na+ binding to ASBT NM does not favor an outward-facing conformation. • DEER distance measurements are in agreement with SDAF profiles. • ASBT NM exists as a monomer in detergent micelles and membranes. • The dynamics studies provide a new viewpoint of elevator-type transporters. Apical sodium-dependent bile acid transporter (ASBT) catalyses uphill transport of bile acids using the electrochemical gradient of Na+ as the driving force. The crystal structures of two bacterial homologues ASBT NM and ASBT Yf have previously been determined, with the former showing an inward-facing conformation, and the latter adopting an outward-facing conformation accomplished by the substitution of the critical Na+-binding residue glutamate-254 with an alanine residue. While the two crystal structures suggested an elevator-like movement to afford alternating access to the substrate binding site, the mechanistic role of Na+ and substrate in the conformational isomerization remains unclear. In this study, we utilized site-directed alkylation monitored by in-gel fluorescence (SDAF) to probe the solvent accessibility of the residues lining the substrate permeation pathway of ASBT NM under different Na+ and substrate conditions, and interpreted the conformational states inferred from the crystal structures. Unexpectedly, the crosslinking experiments demonstrated that ASBT NM is a monomer protein, unlike the other elevator-type transporters, usually forming a homodimer or a homotrimer. The conformational dynamics observed by the biochemical experiments were further validated using DEER measuring the distance between the spin-labelled pairs. Our results revealed that Na+ ions shift the conformational equilibrium of ASBT NM toward the inward-facing state thereby facilitating cytoplasmic uptake of substrate. The current findings provide a novel perspective on the conformational equilibrium of secondary active transporters. [ABSTRACT FROM AUTHOR]