Fifty high resolution protein structures from the Brookhaven Protein Data Bank have been analyzed for recurring motifs in hydrogen bond stereochemistry. Although an exhaustive analysis of hydrogen bond statistics has been presented by Baker & Hubbard, a detailed stereochemical analysis of classical donor (N-H, O-H, or S-H) and acceptor (N:, O:, or S:) structure within proteins is lacking. Here, we describe the preferential hydrogen bond stereochemistry for the side-chains of glutamate and aspartate (carboxylate), glutamine and asparagine (carboxamide), arginine (guanidinium), histidine (imidazole/imidazolium), tryptophan (indole), tyrosine (phenolic hydroxyl), lysine (ammonium), serine and threonine (alkyl hydroxyl), cysteine (thiol), methionine (thioether) and cystine (disulfide). Preferential hydrogen bond stereochemistry is governed by (1) the electronic configuration of acceptor atoms, (2) the steric accessibility of donor atoms and (3) the conformation of amino acid side-chains. Applications of hydrogen bond stereochemistry are useful in the interpretation of protein structure, function and stability. Additionally, this stereochemistry is a prerequisite to the interpretation of protein-other molecule recognition and biological catalysis.
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http://dx.doi.org/10.1016/s0022-2836(05)80364-x | DOI Listing |
Magn Reson Chem
January 2025
Laboratório de Química Computacional e Modelagem Molecular (LQC-MM), Departamento de Química Inorgânica, Instituto de Química, Universidade Federal Fluminense (UFF), Niterói, Rio de Janeiro, Brazil.
We present a DFT-PCM NMR study of 3-indoleacetic acid (3-IAA), used as a working example, including explicit solvent molecules, named PCM-nCHCl, PCM-nDMSO (n = 0, 2, 4, 8, 14, 20, and 25), to investigate the dimer formation in solution. Apart from well-known cyclic (I) and open (II) acetic acid (AA) dimers, two new structures were located on DFT-PCM potential energy surface (PES) for 3-IAA named quasicyclic A (III) and quasicyclic B (IV), the last one having N-H…O hydrogen bond (instead of O-H…O). In addition, four other structures having π-π type interactions named V, VI, VII, and VIII were also obtained completing the sample on the PES.
View Article and Find Full Text PDFInt J Biol Macromol
January 2025
Chemistry Department, Faculty of Women of Arts, Science and Education, Ain Shams University, Heliopolis 11757, Egypt.
This work aimed to synthesize a new acetyl triazolyl uracil (UT) compound and subsequently utilize it to obtain a new chitosan-based Schiff base polymer (CH-UT). The new derivative was characterized using elemental analysis, FTIR, HNMR, XRD, TGA, DSC, and SEM analyses. Both UT and CH-UT were evaluated for their antibacterial activities against various Gram-positive and Gram-negative bacteria.
View Article and Find Full Text PDFChemSusChem
January 2025
CSIR Central Glass & Ceramic Research Institute, EMDD, 196 Raja S C Mullick Road, 700032, Kolkata, INDIA.
The advancement of photocatalytic technology for solar-driven hydrogen (H2) production remains hindered by several challenges in developing efficient photocatalysts. A key issue is the rapid recombination of charge carriers, which significantly limits the light-harvesting ability of materials like BiOCl and Cu2SnS3 quantum dots (CTS QDs), despite the faster charge mobility and quantum confinement effect, respectively. Herein, a BiOCl/CTS (BCTS) heterostructure was synthesized by loading CTS QDs onto BiOCl 2D nanosheets (NSs), that demonstrated excellent photocatalytic activity under visible light irradiation.
View Article and Find Full Text PDFNanomicro Lett
January 2025
Fujian Provincial Key Laboratory of Fire Retardant Materials, College of Materials, Xiamen University, Xiamen, 361000, People's Republic of China.
In recent decades, annual urban fire incidents, including those involving ancient wooden buildings burned, transportation, and solar panels, have increased, leading to significant loss of human life and property. Addressing this issue without altering the surface morphology or interfering with optical behavior of flammable materials poses a substantial challenge. Herein, we present a transparent, low thickness, ceramifiable nanosystem coating composed of a highly adhesive base (poly(SSS-co-HEMA)), nanoscale layered double hydroxide sheets as ceramic precursors, and supramolecular melamine di-borate as an accelerator.
View Article and Find Full Text PDFTalanta
January 2025
School of Pharmacy, Shenyang Pharmaceutical University, Shenyang, 110016, PR China. Electronic address:
Monitoring of p-nitrophenol (PNP) and 3-methyl-4-nitrophenol (PNMC) in human urine and environmental water is of great importance for human health assessment and environmental protection, as they are both urinary metabolites of some poisonous pesticides and priority environmental pollutants. However, efficient extraction of trace levels of PNP and PNMC from complex matrices remains challenging. This study presented the synthesis of histidine-modified ZIF-90 on natural eggshell membrane (ESM@His-ZIF-90) via a facile one-step in-situ growth strategy, and its application as an adsorbent for dispersive membrane extraction (DME) of PNP and PNMC in human urine and environmental water.
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