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Herein, we report a facile approach to develop protein nanoconstructs of cytochrome C with silk nanofibrils in the presence of ionic liquid with improved stability and activity against various harsh conditions.

Of the different classes of halogenases characterized to date, flavin dependent halogenases (FDHs) are most commonly associated with site-selective halogenation of electron rich arenes and enol(ate) moieties in the biosynthesis of halogenated natural products. This capability has made them attractive biocatalysts, and extensive efforts have been devoted to both discovering and engineering these enzymes for different applications. We have established that engineered FDHs can catalyze different enantioselective halogenation processes, including halolactonization of simple alkenes with a tethered carboxylate nucleophile. In this study, we expand the scope of this reaction to include alcohol nucleophiles and a greater diversity of alkene substitution patterns to access a variety of chiral tetrahydrofurans. We also demonstrate that FDHs can be interfaced with ketoreductases to enable halocyclization using ketone substrates in one-pot cascade reactions and that the halocyclization products can undergo subsequent rearrangements to form novel hydroxylated and halogenated products. Together, these advances expand the utility of FDHs for enantio- and diastereoselective olefin functionalization.

Let [Formula: see text] be a Cohen–Macaulay local ring. Let [Formula: see text] be a finitely generated [Formula: see text]-module and let [Formula: see text] denote the [Formula: see text]-dual of [Formula: see text]. Furthermore, if [Formula: see text] is a maximal Cohen–Macaulay [Formula: see text]-module, then we prove that [Formula: see text], where [Formula: see text] is the cardinality of a minimal generating set of [Formula: see text] as an [Formula: see text]-module and [Formula: see text] is the multiplicity of the local ring [Formula: see text]. Furthermore, if [Formula: see text] is a reflexive [Formula: see text]-module then [Formula: see text]. As an application, we study the bound on the minimal number of generators of specific modules over two-dimensional normal local rings. We also mention some relevant examples.

The ability to a site-selectively modify equivalent functional groups in a molecule has the potential to streamline syntheses and increase product yields by lowering step counts. Enzymes catalyze site-selective transformations throughout primary and secondary metabolism, but leveraging this capability for non-native substrates and reactions requires a detailed understanding of the potential and limitations of enzyme catalysis and how these bounds can be extended by protein engineering. In this review, we discuss representative examples of site-selective enzyme catalysis involving functional group manipulation and C-H bond functionalization. We include illustrative examples of native catalysis, but our focus is on cases involving non-native substrates and reactions often using engineered enzymes. We then discuss the use of these enzymes for chemoenzymatic transformations and target-oriented synthesis and conclude with a survey of tools and techniques that could expand the scope of non-native site-selective enzyme catalysis.

Early infection diagnosis is crucial to decrease morbidity and mortality rates. However, complex biological samples, like human blood or serum, contain high abundance proteins and metabolites that reduce the sensitivity of methods used to identify and quantify nucleic acids in bacterial infections diagnosis. To address this issue, we investigated aqueous biphasic systems (ABS) composed of polypropylene glycol 400 and cholinium-based ionic liquids (ILs) at different pH values for the pre-treatment of human serum, aiming the separation of DNA from human serum albumin (HSA) to reduce the interference on the DNA quantification by real-time PCR (qPCR). Remarkable extraction efficiencies of DNA to the IL-rich phase were obtained with all investigated systems, ranging between 90 and 100% in a single-step, with no significant losses of DNA observed (yield at the IL-rich phase > 90%). At low pH values HSA precipitates, whereas at neutral pH no HSA precipitation is observed. This trend suggests that IL-based ABS can be tuned to selectively isolate DNA from HSA by adjusting the pH. The most effective ABS identified is composed of cholinium glycolate at pH 5, allowing to completely precipitate HSA at the ABS interface and leading to an IL-rich phase enriched in DNA with high purity (>98%) that can be quantified by qPCR. Finally, it is shown that the IL-rich phase is able to maintain the DNA’s structural integrity at room temperature, for up to six months, implying that the IL-rich phase of the selected ABS could also be a suitable DNA storage medium. In summary, designed IL-based ABS can be applied as a pretreatment strategy of human serum, allowing to isolate bacterial DNA and opening new perspectives in the monitoring of bacterial infections. published

Green and nano-structured catalytic media are vital for bio-catalysis to attenuate the denaturation tendency of biocata-lysts under severe reaction conditions. Hydrotropes with multi-faceted physiochemical properties represent promising systems for sustainable protein packaging. Herein, the suitability of adenosine-5’-triphosphate (ATP) and cholinium sa-licylate ([Cho][Sal]) ionic liquid (IL) to form nano-structures and to nano-confine Cytochrome c (Cyt c) were demonstrat-ed to enhance the stability and activity under multiple stressors. Experimental and computational analyses were under-taken to explain the nano-structured phenomenon of ATP and IL, structural organizations of nano-confined Cyt c, and site-specific interactions that stabilize the protein structure. Both ATP and IL form nano-structures in aqueous media and could cage Cyt c via multiple nonspecific soft interactions. Remarkably, the engineered molecular nano-cages of ATP (5-10 mM), IL (300 mg/mL), and ATP+IL surrounding Cyt c resulted in 9-to-72-fold higher peroxidase activity than native Cyt c with exceptionally high thermal tolerance (110oC). The polar interactions with the cardiolipin binding site of Cyt c, mediated by hydrotropes, were well correlated with the increased peroxidase activity. Furthermore, higher activity trends were observed in the presence of urea, GuHCl, and trypsin without any protein degradation. Specific binding of hy-drotropes in highly mobile regions of Cyt c (Ω 40-54 residues) and enhanced H-bonding with Lys and Arg offered excel-lent stability under extreme conditions. Additionally, ATP effectively counteracted reactive oxygen species (ROS)-induced denaturation of Cyt c, which was enhanced by the [Sal] counterpart of IL. Overall, this study explored the robustness of nano-structured hydrotropes to have a higher potential for protein packaging with improved stability and activity under extreme conditions. Thus, the present work highlights a novel strategy for real-time industrial bio-catalysis to protect mitochondrial cells from ROS-instigated apoptosis.SummarySuitability of ATP and [Cho][Sal] ionic liquid to form nanostructured hydrotropes and their utility in protein packaging in extreme conditions are discussed. Both ATP and IL form nanostructures in aqueous media and could cage Cyt c via multiple nonspecific soft interactions. The engineered molecular nanocages surrounding Cyt c resulted in 9-to-72-fold higher peroxidase activity than native Cyt c with exceptionally high thermal tolerance (110°C) and stability in the presence of urea, GuHCl, and trypsin without any protein degradation.

Herein, high-performance functional nanomaterials which are demonstrated as efficient adsorbents, membrane materials, and membrane-based water treatment devices are reviewed envisaging simple and scalable water purification technologies.

The unique catalytic properties of enzymes are greatly recognised and led to effective utilisation in the production of useful medicinal intermediates, food industry, and biofuels from sustainable sources. However, the...

Flavin-dependent halogenases (FDHs) natively catalyze selective halogenation of electron rich aromatic and enolate groups. Nearly all FDHs reported to date require a separate flavin reductase to supply them with FADH(2), which complicates biocatalysis applications. In this study, we establish that the single component flavin reductase/flavin dependent halogenase AetF catalyzes halogenation of a diverse set of substrates using a commercially available glucose dehydrogenase to drive its halogenase activity. High site selectivity, activity on relatively unactivated substrates, and high enantioselectivity for atroposelective bromination and bromolactonization was demonstrated. Site-selective iodination and enantioselective cycloiodoetherification was also possible using AetF. The substrate and reaction scope of AetF suggest that it has the potential to greatly improve the utility of biocatalytic halogenation.

The coupled cluster iteration scheme for determining the cluster amplitudes involves a set of nonlinearly coupled difference equations. In the space spanned by the amplitudes, the set of equations are analysed as a multivariate time-discrete map where the concept of time appears in an implicit manner. With the observation that the cluster amplitudes have difference in their relaxation timescales with respect to the distributions of their magnitudes, the coupled cluster iteration dynamics are considered as a synergistic motion of coexisting slow and fast relaxing modes, manifesting a dynamical hierarchical structure. With the identification of the highly damped auxiliary amplitudes, their time variation can be neglected compared to the principal amplitudes which take much longer time to reach the fixed points. We analytically establish the adiabatic approximation where each of these auxiliary amplitudes are expressed as unique parametric functions of the collective principal amplitudes, allowing us to study the optimization with the latter taken as the independent degrees of freedom. Such decoupling of the amplitudes significantly reduces the computational scaling without sacrificing the accuracy in the ground state energy as demonstrated by a number of challenging molecular applications. A road-map to treat higher order post-adiabatic effects is also discussed., 10 Pages, 4 figures

Fe(II)- and α-ketoglutarate-dependent halogenases and oxygenases can catalyze site-selective functionalization of C-H bonds via a variety of C-X bond forming reactions. Achieving high chemoselectivity for functionalization using non-native functional groups remains rare, however, particularly for non-native substrates. The current study shows that directed evolution can be used to engineer variants of an engineered dioxygenase, SadX, that address this challenge. Site-selective azidation of succinylated amino acids and a succinylated amine was achieved using variants with improved azidation yield and selectivity on a probe substrate as a result of mutations throughout the SadX structure. The installed azide group was reduced to a primary amine, and the succinyl group required for azidation was enzymatically cleaved to provide the corresponding amine. These results provide a promising starting point for evolving additional SadX variants with activity on structurally distinct substrates and for enabling enzymatic C-H functionalization with other non-native functional groups.

G-Protein-coupled receptors (GPCRs) belong to an important family of integral membrane receptor proteins that are essential for a variety of transmembrane signaling process, such as vision, olfaction, and hormone responses. They are also involved in many human diseases (Alzheimer's, heart diseases, etc.) and are therefore common drug targets. Thus, understanding the details of the GPCR activation process is a task of major importance. Various types of crystal structures of GPCRs have been solved either at stable end-point states or at possible intermediate states. However, the detailed mechanism of the activation process is still poorly understood. For example, it is not completely clear when the nucleotide release from the G protein occurs and how the key residues on α5 contribute to the coupling process and further affect the binding specificity. In this work we show by free energy analysis that the guanosine diphosphate (GDP) molecule could be released from the Gs protein when the binding cavity is half open. This occurs during the transition to the Gs open state, which is the rate-determining step in the system conformational change. We also account for the experimentally observed slow-down effects by the change of the reaction barriers after mutations. Furthermore, we identify potential key residues on α5 and validated their significance by site-directed mutagenesis, which illustrates that computational works have predictive value even for complex biophysical systems. The methodology of the current work may be applied to other biophysical systems of interest.

Halocyclization of alkenes is a powerful bond-forming tool in synthetic organic chemistry and a key step in natural product biosynthesis, but catalyzing halocyclization with high enantioselectivity remains a challenging task. Identifying suitable enzymes that catalyze enantioselective halocyclization of simple olefins would therefore have significant synthetic value. Flavin-dependent halogenases (FDHs) catalyze halogenation of arene and enol(ate) substrates. Herein, we reveal that FDHs engineered to catalyze site-selective aromatic halogenation also catalyze non-native bromolactonization of olefins with high enantioselectivity and near-native catalytic proficiency. Highly selective halocyclization is achieved by characterizing and mitigating the release of HOBr from the FDH active site using a combination of reaction optimization and protein engineering. The structural origins of improvements imparted by mutations responsible for the emergence of halocyclase activity are discussed. This expansion of FDH catalytic activity presages the development of a wide range of biocatalytic halogenation reactions., Catalytic enantioselective halocyclization of alkenes is an important bond forming tool and a key step in natural product biosynthesis, but so far no examples of the enzymatic counterpart of this reaction on simple achiral olefins have been reported. Here, the authors describe examples of engineered flavin-dependent halogenases that catalyze halolactonization of olefins with high enantioselectivity and near-native catalytic activity.

The appearance and rapid spread of the fall armyworm (Spodoptera frugiperda) (FAW) represents a serious threat to maize cultivation in India and elsewhere in South Asia. Chemical control illustrates one of the major means of reducing the infestation of FAW in maize-growing zones. However, existing information regarding the field-efficacy and non-target toxicity of different insecticides against this pest is not adequate and is also unable to capture the momentum change in the scenario of residual toxicity and insecticide resistance for redacting sustainable management. The present study was framed to establish the most suitable insecticidal schedule against FAW for maize producers. In the period from winter 2019–2020 to spring–summer 2020, seven treatment schedules against FAW were evaluated, and the efficacy was calculated according to the per cent maize plant damage (PD) by larvae, while safety was enumerated based on larval parasitization by Campoletis chlorideae and the abundance of coccinellid predators. In both seasons, the highest cumulative efficacy (9.88 and 10.19% PD) was confirmed for T3 (constituted with Barazide®, Delegate®, and Ampligo®) with a significantly higher yield (52.39 and 52.66 q ha−1), whereas T7 (Proclaim Fit®, Ampligo®, and Delegate®) and T6 (Fimecta®, Ampligo®, and Spintor®) exhibited a high cumulative efficacy (11.06 to 12.23% PD). T3 was found to be safe to coccinellid predators and the per cent larval parasitism by C. chlorideae was significantly higher in this module (2.57 and 2.75%) compared to T4 and T5 (1.00 to 1.67%). The residues of Barazide®, Delegate®, and Ampligo® were below detectable levels in maize plant, grain and soil samples. Therefore, the module could be recommended against FAW in the near future.

An extension of integral domains A⊆B is called a quasi-divisor closed extension if, whenever b1b2∈A for some nonzero b1,b2∈B, then there exist units u, v of B such that b1u,b2v∈A. The notion of a q...

Global water scarcity is increasing day-by-day due to population explosion, urbanization and rapid industrialization. Inevitably, surface water is widely contaminated by various hazardous geogenic, organic and inorganic contaminants, also by untreated industrial effluents and unscientific human activities. On the other hand, the rapid worldwide increase in consumption of petroleum products has inspired researchers to develop renewable and sustainable materials for water purification applications. Significantly, biomass-derived materials are promising substitutes for depleting resources. Specifically, marine-based biomaterials, for instance, chitin/chitosan, seaweeds and seaweed-based polysacharides (agarose, alginate, cellulose, carrageenan) are abundant, environmentally friendly, and renewable biomaterials that are considered an appropriate solution for environmental contamination. Over past few decades various studies have focused on marine-based and seaweed-polysaccharide-based composites because of their renewability and sustainability for water purification. A number of reviews exist for biopolymer-based material applications in water purification; but to promote marine-derived biomaterials for water purification, a critical review between conventional materials and emerging approaches using seaweed-derived materials is needed. Hence, the present review study is the first of its kind, shedding light on the selection of diverse marine-derived biomaterials, as well as their important physical and chemical properties, in order to design functional materials for water purification applications. Further, the present review critically assesses the high-performance marine-derived functional materials exploited for existing state-of-the-art water purification technologies. Marine-derived materials with unique properties, such as inbuilt functionality, high mechanical strength, and prominent surface area and their prominence in developing high-performance sustainable materials for water purifications are reviewed. Furthermore, the review also discusses the various methodologies developed for the preparation of multifunctional carbonaceous materials using marine-derived biomaterials. Such biochar compete with commercial activated carbon and graphene owing to their unique properties. Also, the challenges in implementing the developed functional biomaterials in state-of-the-art water purification technologies and future prospects are discussed.

Blue biorefineries integrate the production of renewable chemicals, fuels, functional materials and marketable commodities utilising biomass of marine origin. The global climate issues, ever-increasing population and depletion of fossil resources make the development of a bioeconomy based on sustainable resources a priority. Green technologies are emerging as a potential aid for developing eco-friendly processes to treat biomass for their conversion into value-added marketable products. New types of solvent systems such as ionic liquids (ILs), deep eutectic solvents (DESs), super critical CO2 (SC-CO2) and biomass-derived solvents are gaining attention for the efficient bioprocessing of natural resources. Due to their distinguished properties, they are promising solvent systems for blue biorefineries. This review summarizes the concept of blue biorefineries, the valuable resources available from the ocean, the marketable commodities developed using marine biomass and the potential of neoteric solvent systems for blue biorefineries.

Large-scale production of graphene sheets by liquid-phase exfoliation of graphite is a challenging task from a sustainability point of view. Certain bio-derived solvents were found to exfoliate graphite to produce single-layered graphene sheets but the high cost of the solvent is always a deterring factor towards upscaling of the process. Herein, Kappaphycus alvarezii, a cultivable red seaweed is demonstrated as a sustainable resource for producing a bio solvent for exfoliation and to produce graphene sheets from graphite. A solvent system consisting of levulinic acid, acetic acid, and γ-valerolactone was prepared from the polysaccharide obtained from the seaweed biomass through acid hydrolysis under pressure and the mixture was found to exfoliate graphite to produce few-layered pristine graphene nanosheets. The process is scalable and cost-effective and the seaweed biomass-derived solvent mixture can be recovered and reused in the subsequent cycles of exfoliation for large-scale production of graphene nanosheets.

In this study, we engineer a variant of the flavin-dependent halogenase RebH that catalyzes site- and atroposelective halogenation of 3-aryl-4(3H)-quinazolinones via kinetic or dynamic kinetic resolution. The required directed evolution uses a combination of random and site-saturation mutagenesis, substrate walking using two probe substrates, and a two-tiered screening approach involving analysis of variant conversion and then enantioselectivity of improved variants. The resulting variant, 3-T, provides >99:1 e.r. for the (M)-atropisomer of the major brominated product, 25-fold improved conversion, and 91-fold improved site-selectivity relative to the parent enzyme on the probe substrate used in the final rounds of evolution. This high activity and selectivity translates well to several additional substrates with varied steric and electronic properties. Computational modeling and docking simulations are used to rationalize the effects of key mutations on substrate scope and site- and atroposelectivity. Given the range of substrates that have been used for atroposelective synthesis via electrophilic halogenation, these results suggest that FDHs could find many additional applications for atroposelective catalysis. More broadly, this study highlights how RebH can be engineered to accept structurally diverse substrates that enable its use for enantioselective catalysis.

Existence of numerous biomolecules results in biological fluids to be extremely crowded. Thus, Macromolecular crowding is an essential phenomenon to sustain active conformation of proteins in biological systems. Herein, double helical deoxyribonucleic acid (B-DNA) is presented for the first time as a biomacromolecular crowding system for sustainable packaging of cytochrome c (Cyt C). The peroxidase activity of Cyt C was investigated in the presence of various concentrations of B-DNA (from salmon milt). At an optimized concentration of 0.125 mg/mL B-DNA, an 11-fold higher catalytic activity was found than in native Cyt C with improved stability. Molecular docking and spectroscopic analyses revealed that electrostatic and H-bonding are the main interactions between DNA and Cyt C that affect the structural stability and activity of the protein. Moreover, the catalytic activity and stability of the protein were further investigated in the presence of severe process conditions by UV-visible, circular dichroism, and Fourier-transform infrared spectroscopies. Molecularly crowded Cyt C showed significantly higher activity and stability under severe environments such as high temperature (110 °C), oxidative stress, high pH (pH 10) and biological (trypsin) and chemical denaturants (urea) compared to bare Cyt C. The observed results support the suitability of DNA-based macromolecular crowding media as a viable and effective stabilizer of proteins against multiple stresses.

Understanding the activation mechanism of the μ-opioid receptor (μ-OR) and its selective coupling to the inhibitory G protein (Gi) is vital for pharmaceutical research aimed at finding treatments for the opioid overdose crisis. Many attempts have been made to understand the mechanism of the μ-OR activation, following the elucidation of new crystal structures such as the antagonist- and agonist-bound μ-OR. However, the focus has not been placed on the underlying energetics and specificity of the activation process. An energy-based picture would not only help to explain this coupling but also help to explore why other possible options are not common. For example, one would like to understand why μ-OR is more selective to Gi than a stimulatory G protein (Gs). Our study used homology modeling and a coarse-grained model to generate all of the possible "end states" of the thermodynamic cycle of the activation of μ-OR. The end points were further used to generate reasonable intermediate structures of the receptor and the Gi to calculate two-dimensional free energy landscapes. The results of the landscape calculations helped to propose a plausible sequence of conformational changes in the μ-OR and Gi system and for exploring the path that leads to its activation. Furthermore, in silico alanine scanning calculations of the last 21 residues of the C terminals of Gi and Gs were performed to shed light on the selective binding of Gi to μ-OR. Overall, the present work appears to demonstrate the potential of multiscale modeling in exploring the action of G protein-coupled receptors.

The wide application of protein fibrils as functional materials has been restricted by the limited scalability of fibrillation methods, slow kinetics, and use of expensive purified proteins. Herein, inspired by the biological cooperativity of proteins in macro-molecularly crowded environments, these restrictions have been overcome. Using ionic liquid cholinium tosylate that acts as a fibrillation agent, instantaneous production of protein fibrils is shown directly from a real and low-cost matrix, i.e. egg white. The fibrillation of egg white proteome is confirmed by microscopy, whereas the fibrillation kinetics is monitored by fluorescence changes of the thioflavin T dye and secondary structural transitions. Spectroscopic and molecular docking studies are used to identify the proteins involved and to appraise the molecular-level mechanisms ruling the proteins structural changes upon fibrillation. The obtained fibrils have enhanced mechanical stiffness and cytocompatibility, demonstrating their potential to act as improved enzyme supports. The applicability of protein fibrils as functional biomaterials is limited due to low scalability of production process, slow kinetics, and requirement of expensive purified proteins. Here, instantaneous production of protein fibrils from egg white proteome using cholinium tosylate as a fibrillation agent is shown, with the obtained fibrils displaying enhanced mechanical stiffness and cytocompatibility.

This article reports the first instance of exploring a chemically Zn(II) preinserted organic–inorganic hybrid material [vanadyl ethylene glycolate or VEG, (VO(CH2O)2)] as an efficient cathode for r...

Antibodies present in mammal's serum are of high relevance for therapeutic purposes, particularly in passive immunization and in the treatment of some chronic diseases. However, their widespread use is still compromised by the requirement of several process steps for their purification and the difficulty in keeping antibodies stable to guarantee their therapeutic efficiency. These challenges significantly contribute to the current high cost of biopharmaceuticals, namely antibodies such as immunoglobulin G (IgG). Accordingly, the development of effective and sustainable purification strategies for antibodies and other biopharmaceuticals is in critical demand to decrease economic, environmental and health burdens. Herein, bio-based and low-cost hybrid alginate–protein cryogel beads were prepared, characterized, and applied as novel adsorbent materials for the purification of IgG from human serum. It is shown that hybrid materials are more efficient than the respective alginate beads since the presence of proteins increases the material selectivity for IgG, which is due to the specific interactions occurring between the target antibody and amino acid residues in the hybrid materials. Several operating conditions, such as pH, adsorption time and serum concentration, were optimized to improve the recovery yield and purity of IgG. Adsorption isotherms were determined to infer the adsorption mechanism of IgG onto the cryogel beads and to determine their adsorption capacity (175 mg of IgG per g of cryogel beads). Under the optimized conditions, IgG can be recovered from the hybrid materials using buffered aqueous solutions, with a purity of 80% and a recovery yield of 91%. The stability and integrity of the antibody are retained after the desorption step. Finally, the regeneration and reuse of the cryogel beads were evaluated, with no losses in the IgG adsorption performance and antibody stability. Although significant efforts have been put on the development of novel affinity ligands to replace the standard chromatographic methods to purify IgG, this work demonstrates the potential of bio-based and low-cost hybrid materials as promising alternatives, in which proteins can be used to improve the material selectivity.

The present work demonstrates an innovative strategy for robust water purification using an engineered aerogel membrane fabricated from biopolymers and task-specific Fe-Al-based nanocomposites. The as-prepared ethylenediaminetetraacetate dianhydride cross-linked chitosan- and agarose (7:3 weight ratio)-based aerogel membrane decorated with α-FeOOH- and γ-AlOOH-based nanocomposites was characterized using various analytical tools, which suggested formation of a highly stable network interconnected through covalent and electrostatic interactions. The optimized bionanocomposite-based aerogel (BNC-AG-0.1) membrane showed macroporous and partial unidirectional short-range channels with an ultralow density of 0.021 g·m

Recent decade has seen enormous interest in developing cost effective, simple and greener method of utilizing naturally abundant and renewable resources to mitigate the concerns relating contaminated water sources and store green energy. Carbon materials derived from biomass have drawn great attention because of their abundance, easy processability, tunable surface properties and relatively low cost. Present work demonstrates the conversion of abundant and toxic weed, Parthenium hysterophorous to porosity enriched ultrahigh surface area activated carbon with a surface area of 4014 m2/g and a large porous volume of 2.0419 cm3/g. The optimized carbon materials before and after activation showed crumpled sheet-like morphology with oxygenated functionalities (C/O = 6.352) as confirmed by different analytical tools. Electrochemical studies revealed that the supercapacitor device assembled using the as prepared carbon material manifest an significant specific capacitance of 270 F/g, exhibiting excellent capacity retention of 98.5 % even after 30,000 cycles at an increased current density of 10 A/g. Further, a membrane was prepared using functional carbon material for the removal of different organic pollutants such as dyes (methylene blue, malachite green, eriochrome black T, congo red) and pharmaceutical wastes (paracetamol, ciprofloxacin) from aqueous media. The functional carbon based membrane showed high rejection for cationic dyes (93–99.5%) comparing to anionic dyes (46–67%) with a flux rate in the range of 820–840 Lm-2h−1 and maximum adsorption capacity of 194 mg/g for methylene blue dye. Similarly, for cationic pharmaceutical wastes higher rejection (90–95%) was achieved with an average flux of 830 Lm-2h−1. Moreover, recyclability studies of the membrane affirmed a retention of 91.6% rejection of methylene blue even after 10 consecutive cycles without compromising the flux rate which confirmed the suitability of the toxic weed derived functional carbon as a sustainable alternative for water purification in a continuous flow method.

Triggering receptor expressed on myeloid cells 2 (TREM2) is a single-pass transmembrane receptor of the immunoglobulin superfamily that is secreted in a soluble (sTREM2) form. Mutations in TREM2 have been linked to increased risk of Alzheimer’s disease (AD). A prominent neuropathological component of AD is deposition of the amyloid-β (Aβ) into plaques, particularly Aβ40 and Aβ42. While the membrane-bound form of TREM2 is known to facilitate uptake of Aβ fibrils and the polarization of microglial processes toward amyloid plaques, the role of its soluble ectodomain, particularly in interactions with monomeric or fibrillar Aβ, has been less clear. Our results demonstrate that sTREM2 does not bind to monomeric Aβ40 and Aβ42, even at a high micromolar concentration, while it does bind to fibrillar Aβ42 and Aβ40 with equal affinities (2.6 ± 0.3 µM and 2.3 ± 0.4 µM). Kinetic analysis shows that sTREM2 inhibits the secondary nucleation step in the fibrillization of Aβ, while having little effect on the primary nucleation pathway. Furthermore, binding of sTREM2 to fibrils markedly enhanced uptake of fibrils into human microglial and neuroglioma derived cell lines. The disease-associated sTREM2 mutant, R47H, displayed little to no effect on fibril nucleation and binding, but it decreased uptake and functional responses markedly. We also probed the structure of the WT sTREM2–Aβ fibril complex using integrative molecular modeling based primarily on the cross-linking mass spectrometry data. The model showsthat sTREM2 binds fibrils along one face of the structure, leaving a second, mutation-sensitive site free to mediate cellular binding and uptake.

Lignin is one of the world’s most abundant organic polymers, and 2-pyrone-4,6-dicarboxylate lactonase (LigI) catalyzes the hydrolysis of 2-pyrone-4,6-dicarboxylate (PDC) in the degradation of lignin. The pH has profound effects on enzyme catalysis and therefore we studied this in the context of LigI. We found that changes of the pH mostly affects surface residues, while the residues at the active site are more subject to changes of the surrounding microenvironment. In accordance with this, a high pH facilitates the deprotonation of the substrate. Detailed free energy calculations by the empirical valence bond (EVB) approach revealed that the overall hydrolysis reaction is more likely when the three active site histidines (His31, His33 and His180) are protonated at the ɛ site, however, protonation at the δ site may be favored during specific steps of reaction. Our studies have uncovered the determinant role of the protonation state of the active site residues His31, His33 and His180 in the hydrolysis of PDC.

G-Protein-coupled receptors (GPCRs) belong to an important family of integral membrane receptor proteins that are essential for a variety of transmembrane signaling process, such as vision, olfaction, and hormone responses. They are also involved in many human diseases (Alzheimer's, heart diseases, etc.) and are therefore common drug targets. Thus, understanding the details of the GPCR activation process is a task of major importance. Various types of crystal structures of GPCRs have been solved either at stable end-point states or at possible intermediate states. However, the detailed mechanism of the activation process is still poorly understood. For example, it is not completely clear when the nucleotide release from the G protein occurs and how the key residues on α5 contribute to the coupling process and further affect the binding specificity. In this work we show by free energy analysis that the guanosine diphosphate (GDP) molecule could be released from the G

Metallized DNA is an exciting functional material having widespread utility toward multifunctional applications. However, conventional DNA metallization processes are time-consuming and multistep a...