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The proper function of enzymes often depends upon their efficient interconversion between particular conformational sub-states on a free-energy landscape. Experimentally characterizing these sub-states is challenging, which has limited our understanding of the role of protein dynamics in many enzymes. Here, we have used a combination of kinetic crystallography and detailed analysis of crystallographic protein ensembles to map the accessible conformational landscape of an insect carboxylesterase (LcαE7) as it traverses all steps in its catalytic cycle. LcαE7 is of special interest because of its evolving role in organophosphate insecticide resistance. Our results reveal that a dynamically coupled network of residues extends from the substrate-binding site to a surface loop. Interestingly, the coupling of this network that is apparent in the apoenzyme appears to be reduced in the phosphorylated enzyme intermediate. Altogether, the results of this work highlight the importance of protein dynamics to enzyme function and the evolution of new activity.
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http://dx.doi.org/10.1016/j.str.2016.04.009 | DOI Listing |
Food Res Int
November 2025
Department of Seafood Science, National Kaohsiung University of Science and Technology, Kaohsiung 811, Taiwan. Electronic address:
Dipeptidyl-peptidase (DPP)-IV inhibition by penultimate N-terminus Pro-containing peptides is a promising strategy for Type 2 diabetes (T2D) management, as it prevents the degradation of incretin hormones (DPP-IV substrates) like glucagon-like peptide-1 (GLP-1), thereby prolonging their half-life. However, the stability and bio-accessibility of these peptides are crucial to their efficacy in orally administered therapeutics. We previously identified LPCL and TPFLPDE peptides from tilapia viscera by-products hydrolysates, which exhibited significant DPP-IV inhibition in vitro and in situ while effectively preserving active GLP-1 levels after 2 h treatment in STC-1 cells under basal glucose conditions.
View Article and Find Full Text PDFJBMR Plus
October 2025
Department of Endocrinology and Diabetes, Sir Charles Gairdner Hospital, Nedlands, WA, 6009, Australia.
Genome-wide association studies (GWAS) relevant to osteoporosis have identified hundreds of loci; however, understanding how these variants influence the phenotype is complicated because most reside in non-coding DNA sequence that serves as transcriptional enhancers and repressors. To advance knowledge on these regulatory elements in osteoclasts (OCs), we performed Micro-C analysis, which informs on the genome topology of these cells and integrated the results with transcriptome and GWAS data to further define loci linked to BMD. Using blood cells isolated from 4 healthy participants aged 31-61 yr, we cultured OC in vitro and generated a Micro-C chromatin conformation capture dataset.
View Article and Find Full Text PDFJ Biomol Struct Dyn
September 2025
Enzyme and Microbial Technology Research Center, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, Serdang, Selangor, Malaysia.
A thermostable paraoxonase (S3wahi-PON) from sp. strain S3wahi was recently characterised and shown to possess stability across a broad temperature range. This study expands upon the initial biochemical characterisation of S3wahi-PON by investigating the structural determinants and conformational adaptability that contribute to its thermostability, using an integrated approach that combines biophysical techniques and molecular dynamics (MD) simulations across a temperature range of 10 °C to 90 °C.
View Article and Find Full Text PDFJ Am Chem Soc
September 2025
Clemens-Schöpf-Institut für Organische Chemie und Biochemie, Technische Universität Darmstadt, Peter-Grünberg-Str. 16, 64287 Darmstadt, Germany.
Helical structures are ubiquitous in nature and exhibit fascinating properties. They are inherently chiral, and many rely on hydrogen bonds to stabilize their conformation. Homopolypeptides of the glutamate type form α-helical secondary structures and are considered rigid-rod polymers.
View Article and Find Full Text PDFJ Phys Chem A
September 2025
Department of Chemistry, Virginia Commonwealth University, Richmond, Virginia 23284, United States.
Ionization of alkanes to form radical cations activates their otherwise unreactive C-H bonds, facilitating important chemical processes such as hydrocarbon cracking. This work investigates the radical cation dissociation dynamics of hexane (CH) structural isomers by using femtosecond time-resolved mass spectrometry and quantum chemical calculations. All five isomers exhibit competition between the yields of fragment ions arising from direct C-C bond cleavage or dissociative rearrangement with hydrogen migration on dynamical time scales of ∼50-300 fs, suggesting that hydrogen migration in the metastable cations operates on such short time scales.
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