64,334 results match your criteria hydrophobic interactions


Separation of vigabatrin enantiomers using mixed-mode chromatography and its application to determine the vigabatrin enantiomer levels in rat plasma.

J Chromatogr B Analyt Technol Biomed Life Sci 2021 Jul 27;1179:122866. Epub 2021 Jul 27.

Department of Analytical Chemistry, Faculty of Pharmaceutical Sciences, Toho University, 2-2-1 Miyama, Funabashi-shi, Chiba 274-8510, Japan. Electronic address:

Mixed-mode chromatography-comprising a mixed phase with reversed and ionic phases, enabling hydrophobic and ion-exchange interactions simultaneously-was applied to identify vigabatrin enantiomers by HPLC with pre-column fluorescence derivatization with 2,5-dioxopyrrolidin-1-yl (4-(((2-nitrophenyl)sulfonyl)oxy)-6-(3-oxomorpholino)quinoline-2-carbonyl)prolinate (Ns-MOK-(S)-Pro-OSu). The MOK-(S)-Pro-vigabatrin enantiomers were efficiently separated within 12 min (total analysis time per sample: 28 min, including washing and equilibrium time for the column). The mobile phase was HO/CHOH/10 mM ammonium formate (pH 2. Read More

View Article and Full-Text PDF

Anticancer activity and toxicity of new quaternary ammonium geldanamycin derivative salts and their mixtures with potentiators.

J Enzyme Inhib Med Chem 2021 Dec;36(1):1898-1904

Faculty of Chemistry, Adam Mickiewicz University, Poznan, Poland.

Geldanamycin () has been modified by different type neutral/acidic/basic substituents (-) and by quinuclidine motif (), transformed into ammonium salts (-) at C(17). These compounds have been characterised by spectroscopic and x-ray methods. Derivative shows better potency than in MCF-7, MDA-MB-231, A549 and HeLa (ICs = 0. Read More

View Article and Full-Text PDF
December 2021

Influential mechanism of water occurrence states of waste-activated sludge: specifically focusing on the roles of EPS micro-spatial distribution and cation-dominated interfacial properties.

Water Res 2021 Jul 27;202:117461. Epub 2021 Jul 27.

State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China. Electronic address:

The highly hydrated colloidal structure of waste-activated sludge (WAS) is the main obstacle of enhanced dewatering for sludge volume minimization. Extracellular polymeric substances (EPS) maintain the colloidal stability of bio-flocs in a three-dimensional matrix due to bindings with bivalent cations (i.e. Read More

View Article and Full-Text PDF

In-silico HMG-CoA reductase-inhibitory and in-vivo anti-lipidaemic/anticancer effects of carotenoids from Spondias mombin.

J Pharm Pharmacol 2021 Aug 3. Epub 2021 Aug 3.

Department of Biochemistry, Adekunle Ajasin University, Akungba-Akoko, Ondo State, Nigeria.

Objectives: Inhibition of HMG-CoA (3-hydroxy-3-methylglutaryl coenzyme A) reductase, the rate rate-determining enzyme for the biogenesis of cholesterol is known to show antineoplastic effects. Therefore, this study investigates the in-silico HMG-CoA reductase (HMGCR)-inhibitory and in-vivo anti-lipidaemic/anticancer effects of carotenoids from Spondias mombin.

Methods: Carotenoids from S. Read More

View Article and Full-Text PDF

Quantitative NMR Study of Insulin-Degrading Enzyme Using Amyloid-β and HIV-1 p6 Elucidates Its Chaperone Activity.

Biochemistry 2021 Aug 3. Epub 2021 Aug 3.

Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093, United States.

Insulin-degrading enzyme (IDE) hydrolyzes monomeric polypeptides, including amyloid-β (Aβ) and HIV-1 p6. It also acts as a nonproteolytic chaperone to prevent Aβ polymerization. Here we compare interactions of Aβ and non-amyloidogenic p6 with IDE. Read More

View Article and Full-Text PDF

Structural studies of complexes of kallikrein 4 with wild-type and mutated forms of the Kunitz-type inhibitor BbKI.

Acta Crystallogr D Struct Biol 2021 Aug 29;77(Pt 8):1084-1098. Epub 2021 Jul 29.

Center for Structural Biology, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702, USA.

Structures of BbKI, a recombinant Kunitz-type serine protease inhibitor from Bauhinia bauhinioides, complexed with human kallikrein 4 (KLK4) were determined at medium-to-high resolution in four crystal forms (space groups P321, P622, P2 and P6). Although the fold of the protein was virtually identical in all of the crystals, some significant differences were observed in the conformation of Arg64 of BbKI, the residue that occupies the S1 pocket in KLK4. Whereas this residue exhibited two orientations in the highest resolution structure (P321), making either a canonical trypsin-like interaction with Asp189 of KLK4 or an alternate interaction, only a single alternate orientation was observed in the other three structures. Read More

View Article and Full-Text PDF

Temperature-Dependent Photoluminescence of Hexafluorobenzene Intercalated Phenethylammonium Tin Iodide 2D Perovskite.

Chem Asian J 2021 Aug 3. Epub 2021 Aug 3.

Indian Institute of Science Education and Research (IISER) Pune, Chemistry, Dr. Homi Bhabha Road, 411008, Pune, INDIA.

Tin halide perovskites are the potential alternatives of lead halide perovskites. However, the easy oxidation of Sn 2+ to Sn 4+ brings in a challenge. Recently, layered two dimensional hybrid tin halide perovskites have been shown to partially resist the oxidation process because of the presence of hydrophobic organic molecules. Read More

View Article and Full-Text PDF

Multiple evidences of dynamic heterogeneity in hydrophobic deep eutectic solvents.

J Chem Phys 2021 Jul;155(4):044502

Department of Chemistry, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India.

Hydrophobic deep eutectic solvents (HDESs) have gained immense popularity because of their promising applications in extraction processes. Herein, we employ atomistic molecular dynamics simulations to unveil the dynamics of DL-menthol (DLM) based HDESs with hexanoic (C6), octanoic (C8), and decanoic (C10) acids as hydrogen bond donors. The particular focus is on understanding the nature of dynamics with changing acid tail length. Read More

View Article and Full-Text PDF

Conditioning Film and Early Biofilm Succession on Plastic Surfaces.

Environ Sci Technol 2021 Aug 2. Epub 2021 Aug 2.

Department of Bioanalytical Ecotoxicology, Helmholtz Centre for Environmental Research-UFZ, Permoserstr. 15, 04318 Leipzig, Germany.

In the context of environmental plastic pollution, it is still under debate if and how the "plastisphere", a plastic-specific microbial community, emerges. In this study, we tested the hypothesis that the first conditioning film of dissolved organic matter (DOM) sorbs selectively to polymer substrates and that microbial attachment is governed in a substrate-dependent manner. We investigated the adsorption of stream water-derived DOM to polyethylene terephthalate (PET), polystyrene (PS), and glass (as control) including UV-weathered surfaces by Fourier-transform ion cyclotron mass spectrometry. Read More

View Article and Full-Text PDF

Identification of the structural features of quinazoline derivatives as EGFR inhibitors using 3D-QSAR modeling, molecular docking, molecular dynamics simulations and free energy calculations.

J Biomol Struct Dyn 2021 Aug 2:1-16. Epub 2021 Aug 2.

State Key Laboratory of Functions and Applications of Medicinal Plants, College of Basic Medical, Guizhou Medical University, Guizhou, China.

Epidermal growth factor receptor (EGFR) is a promising target for the treatment of different types of malignant tumors. Therefore, a combined molecular modeling study was performed on a series of quinazoline derivatives as EGFR inhibitors. The optimum ligand-based CoMFA and CoMSIA models showed reliable and satisfactory predictability (with R=0. Read More

View Article and Full-Text PDF

Assessment of the CASP14 Assembly Predictions.

Proteins 2021 Aug 1. Epub 2021 Aug 1.

Izmir Biomedicine and Genome Center, Izmir, Turkey.

In CASP14, 39 research groups submitted more than 2,500 3D models on 22 protein complexes. In general, the community performed well in predicting the fold of the assemblies (for 80% of the targets), though it faced significant challenges in reproducing the native contacts. This is especially the case for the complexes without whole-assembly templates. Read More

View Article and Full-Text PDF

Computational Insights Into the Inhibition Mechanism of Proanthocyanidin B2 on Tau Hexapeptide (PHF6) Oligomer.

Front Chem 2021 14;9:666043. Epub 2021 Jul 14.

School of Pharmacy, Lanzhou University, Lanzhou, China.

The formation of amyloid fibrils from Tau is a key pathogenic feature of Alzheimer's disease (AD). To disturb the formation of Tau aggregates is considered as a promising therapeutic strategy for AD. Recently, a natural product proanthocyanidin B2 (PB2) was confirmed to not only inhibit Tau aggregation, but also disaggregate Tau fibrils. Read More

View Article and Full-Text PDF

How properties of low molecular weight model competitors impact organic micropollutant adsorption onto activated carbon at realistically asymmetric concentrations.

Water Res 2021 Jul 18;202:117443. Epub 2021 Jul 18.

Department of Water Management, Delft University of Technology, PO Box 5048, 2600 GA, Delft, the Netherland; Chair of Water Quality Control, Technische Universität Berlin, KF4, Str. des 17. Juni 135, Berlin 10623, Germany; Berliner Wasserbetriebe, Motardstr. 35, Berlin 13629, Germany.

Low molecular weight (LMW) dissolved organic matter (DOM) is the predominant competitor for adsorption sites against organic micropollutants (OMPs) in activated carbon adsorption. However, top-down approaches using highly complex mixtures of real water DOM do not allow to concisely examine the impacts of specific LMW DOM molecular properties on competitive adsorption. Therefore, we followed a bottom-up approach using fifteen model compounds (mDOM) to elucidate how important DOM characteristics, including hydrophobicity and unsaturated structures (ring, double/triple bond), impact competitiveness. Read More

View Article and Full-Text PDF

Structure-based virtual screening suggests inhibitors of 3-Chymotrypsin-Like Protease of SARS-CoV-2 from Vernonia amygdalina and Occinum gratissimum.

Comput Biol Med 2021 Jul 21;136:104671. Epub 2021 Jul 21.

Human Nutraceuticals and Bioinformatics Research Unit, Department of Biochemistry, Salem University, Nigeria.

Antiviral culinary plants are potential bioresources for preventive nutraceuticals and/or antiviral drugs in COVID-19. Structure-based virtual screening was undertaken to screen 173 compounds previously reported from Vernonia amygdalina and Occinum gratissimum for direct interaction with the active site of the 3-Chymotrypsin-Like Protease (3CL) of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Based on docking scores and comparison with reference inhibitors, a hit-list of 10 top phytocompounds was defined, which also had strong interactions with the catalytic centre of 3CL from three related strains of coronavirus (SARS-CoV, MERS-CoV, HKU4). Read More

View Article and Full-Text PDF

Methodological approaches for the analysis of transmembrane domain interactions: A systematic review.

Biochim Biophys Acta Biomembr 2021 Jul 28:183712. Epub 2021 Jul 28.

Department of Biochemistry and Molecular Biology, Institute for Biotechnology and Biomedicine BioTecMed, University of Valencia, Dr. Moliner 50, 46100 Burjassot, Spain. Electronic address:

The study of protein-protein interactions (PPI) has proven fundamental for the understanding of the most relevant cell processes. Any protein domain can participate in PPI, including transmembrane (TM) segments that can establish interactions with other TM domains (TMDs). However, the hydrophobic nature of TMDs and the environment they occupy complicates the study of intramembrane PPI, which demands the use of specific approaches and techniques. Read More

View Article and Full-Text PDF

Sorption of endocrine disrupting compounds onto polyamide microplastics under different environmental conditions: Behaviour and mechanism.

Sci Total Environ 2021 Jul 10;796:148983. Epub 2021 Jul 10.

Instituto de Química, Universidade Federal do Rio Grande do Sul (UFRGS), Av. Bento Gonçalves, 9500, Porto Alegre 91501-970, RS, Brazil. Electronic address:

Microplastics of polyamide are commonly found in aquatic environments and might act as vectors of different contaminants such as endocrine disrupting compounds (EDC). Therefore, sorption of 17α-ethynylestradiol (EE2), 17β-estradiol (E2), and estriol (E3) on polyamide microplastics was studied under different simulated environments. The results suggest that the sorption process was affected by the presence of dissolved organic matter (DOM) and salinity, where both positive and negative effects were observed. Read More

View Article and Full-Text PDF

Interactions between Acrylate/Methacrylate Biomaterials and Organic Foulants Evaluated by Molecular Dynamics Simulations of Simplified Binary Mixtures.

ACS Biomater Sci Eng 2021 Jul 30. Epub 2021 Jul 30.

Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya-shi, Aichi 466-8555, Japan.

Improving hydrophilicity is a key factor for enhancing the biocompatibility of polymer surfaces. Nevertheless, previous studies have reported that poly(2-methoxyethyl acrylate) (PMEA) surfaces demonstrate markedly better biocompatibility than more hydrophilic poly(2-hydroxyethyl methacrylate) (PHEMA) surfaces. In this work, the origins of the excellent biocompatibility of the PMEA surface are investigated using molecular dynamics (MD) simulations of simplified binary mixtures of acrylate/methacrylate trimers and organic solvents, with -nonane, 1,5-pentanediol, or 1-octanol serving as the probe organic foulants. Read More

View Article and Full-Text PDF

Catalytic Mechanism of Butane Anaerobic Oxidation for Alkyl-coenzyme M Reductase.

Chem Biol Drug Des 2021 Jul 30. Epub 2021 Jul 30.

State Key Laboratory of Microbial Metabolism, Department of Bioinformatics and Biostatistics, SJTU-Yale Joint Center for Biostatistics, National Experimental Teaching Center for Life Sciences and Biotechnology, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China.

Methane is among the most potent of the greenhouse gases, which plays a key role in global climate change. As an excellent carbon and energy source, methane can be utilized by anaerobic methane oxidizing archaea and aerobic methane oxidizing bacteria. The previous work shows that an anaerobic thermophilic enrichment culture composed of dense consortia of archaea and bacteria apparently uses partly similar pathways to oxidize the C4 hydrocarbon butane. Read More

View Article and Full-Text PDF

Structure and mechanism of secondary sulfonamide binding to carbonic anhydrases.

Eur Biophys J 2021 Jul 30. Epub 2021 Jul 30.

Department of Biothermodynamics and Drug Design, Institute of Biotechnology, Life Sciences Center, Vilnius University, Saulėtekio 7, 10257, Vilnius, Lithuania.

Zinc-containing metalloenzyme carbonic anhydrase (CA) binds primary sulfonamides with extremely high, up to picomolar, affinity by forming a coordination bond between the negatively charged amino group and the zinc ion and making hydrogen bonds and hydrophobic contacts with other parts of the inhibitor molecule. However, N-methyl-substituted, secondary or tertiary sulfonamides bind CA with much lower affinity. In search for an explanation for this diminished affinity, a series of secondary sulfonamides were synthesized and, together with analogous primary sulfonamides, the affinities for 12 recombinant catalytically active human CA isoforms were determined by the fluorescent thermal shift assay, stopped-flow assay of the inhibition of enzymatic activity and isothermal titration calorimetry. Read More

View Article and Full-Text PDF

Water and the Cation-π Interaction.

J Am Chem Soc 2021 Jul 30. Epub 2021 Jul 30.

Center for Supramolecular Chemistry & Catalysis and Department of Chemistry, College of Science, Shanghai University, 99 Shang-Da Road, Shanghai 200444, China.

The cation-π interaction and the hydrophobic effect are important intermolecular forces in chemistry and play major roles in controlling recognition in biological systems. We compared their relative contributions to the binding of molecular "dumbbell" guests in synthetic container hosts in water. The guests offered direct, intramolecular competition between trimethylammonium groups, -N(CH), and -butyl groups, -C(CH), for the internal surfaces (aromatic panels) of the containers. Read More

View Article and Full-Text PDF

Insulin- and cholic acid-loaded zein/casein-dextran nanoparticles enhance the oral absorption and hypoglycemic effect of insulin.

J Mater Chem B 2021 Jul 30. Epub 2021 Jul 30.

State Key Laboratory of Molecular Engineering of Polymers, Collaborative Innovation Center of Polymers and Polymer Composite Materials, Department of Macromolecular Science, Fudan University, Shanghai 200438, China.

Diabetes mellitus is the most common metabolic disease in the world. Herein, insulin- and cholic acid-loaded zein nanoparticles with dextran surfaces were fabricated to enhance the oral absorptions of insulin in the intestine and in the liver which is the primary action organ of endogenous insulin. In the nanoparticles, zein acted as cement to embed insulin, cholic acid and casein by hydrophobic interactions. Read More

View Article and Full-Text PDF

Ionic-Liquid-Catalyzed Approaches under Metal-Free Conditions.

Acc Chem Res 2021 Jul 30. Epub 2021 Jul 30.

Beijing National Laboratory for Molecular Sciences, Key Laboratory of Colloid, Interface and Thermodynamics, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.

ConspectusMetal-free catalysis is a promising protocol to access chemicals without metal contamination. Ionic liquids (ILs) that are entirely composed of organic cations and inorganic/organic anions have emerged as promising alternatives to molecular solvents and metal catalysts due to their unique properties such as structural tunability, the coexistence of multiple interactions among ions (e.g. Read More

View Article and Full-Text PDF

Characterizing the binding interactions of sodiumbenzoatewithlysozymeat the molecular level using multi-spectroscopy, ITC and modeling methods.

Spectrochim Acta A Mol Biomol Spectrosc 2021 Jul 22;263:120213. Epub 2021 Jul 22.

School of Environmental Science and Engineering, Shandong University, China-America CRC for Environment & Health, Shandong Province, 72# Jimo Binhai Road, Qingdao, Shandong, 266237, PR China. Electronic address:

In this paper, we mainly study the interaction mechanism between food additives and antioxidant enzymes. Spectral methods were used to study the effect of sodium benzoate on the structure and function of lysozyme at the molecular level. Multi-spectroscopic results showed that sodium benzoate statically quenched the intrinsic fluorescence of lysozyme, formed complexes with lysozyme, increased the polarity of the aromatic amino acid, effected the molecular skeleton of lysozyme and stretched the secondary structure. Read More

View Article and Full-Text PDF

Development of polymer-based nanoparticles for Zileuton delivery to the lung: PMeOx and PMeOzi surface chemistry reduces interactions with mucins.

Nanomedicine 2021 Jul 26:102451. Epub 2021 Jul 26.

Lab of Biocompatible Polymers, Department of Biological, Chemical and Pharmaceutical Sciences and Technologies (STEBICEF), University of Palermo, via Archirafi 32, Palermo, 90123, Italy. Electronic address:

In this paper, two amphiphilic graft copolymers were synthesized by grafting polylactic acid (PLA) as hydrophobic chain and poly(2-methyl-2-oxazoline) (PMeOx) or poly(2-methyl-2-oxazine) (PMeOzi) as hydrophilic chain, respectively, to a backbone of α,β-poly(N-2-hydroxyethyl)-D,L-aspartamide (PHEA). These original graft copolymers were used to prepare nanoparticles delivering Zileuton in inhalation therapy. Among various tested methods, direct nanoprecipitation proved to be the best technique to prepare nanoparticles with the smallest dimensions, the narrowest dimensional distribution and a spherical shape. Read More

View Article and Full-Text PDF

Nanoscale Model System for the Human Myelin Sheath.

Biomacromolecules 2021 Jul 29. Epub 2021 Jul 29.

Interdisciplinary Research Center HALOmem, Martin Luther University (MLU) Halle-Wittenberg, Charles Tanford Protein Center, Kurt-Mothes-Straße 3a, 06120 Halle (Saale), Germany.

Neurodegenerative disorders are among the most common diseases in modern society. However, the molecular bases of diseases such as multiple sclerosis or Charcot-Marie-Tooth disease remain far from being fully understood. Research in this field is limited by the complex nature of native myelin and by difficulties in obtaining good in vitro model systems of myelin. Read More

View Article and Full-Text PDF

Synthesis and Identification of Novel Potential Molecules Against COVID-19 Main Protease Through Structure-Guided Virtual Screening Approach.

Appl Biochem Biotechnol 2021 Jul 29. Epub 2021 Jul 29.

Laboratoire de Chimie Organique Hétérocyclique, URAC 21, Pôle de Compétences Pharmaco-Chimie, Faculté Des Sciences, Université Mohammed V, BP 10014, Rabat, Morocco.

The novel coronavirus disease that arises in the end of 2019 (COVID-19) in Wuhan, China, has rapidly spread over the globe and was considered as a world pandemic. Currently, various antiviral therapies or vaccines are available, and many researches are ongoing for further treatments. Targeting the coronavirus' main protease (key enzyme: 3CLpro) is growing in importance in anti-SARS-CoV-2 drug discovery process. Read More

View Article and Full-Text PDF

Structural basis of ketamine action on human NMDA receptors.

Nature 2021 Jul 28. Epub 2021 Jul 28.

Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, China.

Ketamine is a non-competitive channel blocker of N-methyl-D-aspartate (NMDA) receptors. A single sub-anaesthetic dose of ketamine produces rapid (within hours) and long-lasting antidepressant effects in patients who are resistant to other antidepressants. Ketamine is a racemic mixture of S- and R-ketamine enantiomers, with S-ketamine isomer being the more active antidepressant. Read More

View Article and Full-Text PDF

Nanopore Stochastic Sensing Based on Non-covalent Interactions.

Anal Chem 2021 Jul 28. Epub 2021 Jul 28.

Department of Chemistry, Illinois Institute of Technology, 3101 S. Dearborn Street, Chicago, Illinois 60616, United States.

A variety of species could be detected by using nanopores engineered with various recognition sites based upon non-covalent interactions, including electrostatic, aromatic, and hydrophobic interactions. The existence of these engineered non-covalent bonding sites was supported by the single-channel recording technique. The advantage of the non-covalent interaction-based sensing strategy was that the recognition site of the engineered nanopore was not specific for a particular molecule but instead selective for a class of species (e. Read More

View Article and Full-Text PDF

Thermoresponsive interfaces obtained using poly(N-isopropylacrylamide)-based copolymer for bioseparation and tissue engineering applications.

Authors:
Kenichi Nagase

Adv Colloid Interface Sci 2021 Jul 14;295:102487. Epub 2021 Jul 14.

Faculty of Pharmacy, Keio University, 1-5-30 Shibakoen, Minato, Tokyo 105-8512, Japan. Electronic address:

Poly(N-isopropylacrylamide) (PNIPAAm) is the most well-known and widely used stimuli-responsive polymer in the biomedical field owing to its ability to undergo temperature-dependent hydration and dehydration with temperature variations, causing hydrophilic and hydrophobic alterations. This temperature-dependent property of PNIPAAm provides functionality to interfaces containing PNIPAAm. Notably, the hydrophilic and hydrophobic alterations caused by the change in the temperature-responsive property of PNIPAAm-modified interfaces induce temperature-modulated interactions with biomolecules, proteins, and cells. Read More

View Article and Full-Text PDF

Determination of Ligand Binding Modes in Hydrated Viral Ion Channels to Foster Drug Design and Repositioning.

J Chem Inf Model 2021 Jul 27. Epub 2021 Jul 27.

Pharmacoinformatics Unit, Department of Pharmacology and Pharmacotherapy, Medical School, University of Pécs, Szigeti út 12, 7624 Pécs, Hungary.

Target-based design and repositioning are mainstream strategies of drug discovery. Numerous drug design and repositioning projects have been launched to fight the ongoing COVID-19 pandemic. The resulting drug candidates have often failed due to the misprediction of their target-bound structures. Read More

View Article and Full-Text PDF