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Title: Engineering Dynamic Surface Peptide Networks on ButyrylcholinesteraseG117H for Enhanced Organophosphosphorus Anticholinesterase Catalysis.

Authors: Hester, Kirstin P; Bhattarai, Krishna; Jiang, Haobo; Agarwal, Pratul K; Pope, Carey

Published In Chem Res Toxicol, (2019 09 16)

Abstract: The single residue mutation of butyrylcholinesterase (BChEG117H) hydrolyzes a number of organophosphosphorus (OP) anticholinesterases. Whereas other BChE active site/proximal mutations have been investigated, none are sufficiently active to be prophylactically useful. In a fundamentally different computer simulations driven strategy, we identified a surface peptide loop (residues 278-285) exhibiting dynamic motions during catalysis and modified it via residue insertions. We evaluated these loop mutants using computer simulations, substrate kinetics, resistance to inhibition, and enzyme reactivation assays using both the choline ester and OP substrates. A slight but significant increase in reactivation was noted with paraoxon with one of the mutants, and changes in KM and catalytic efficiency were noted in others. Simulations suggested weaker interactions between OP versus choline substrates and the active site of all engineered versions of the enzyme. The results indicate that an improvement of OP anticholinesterase hydrolysis through surface loop engineering may be a more effective strategy in an enzyme with higher intrinsic OP compound hydrolase activity.

PubMed ID: 31411024 Exiting the NIEHS site

MeSH Terms: Biocatalysis; Butyrylcholinesterase/chemistry*; Butyrylcholinesterase/genetics; Butyrylcholinesterase/metabolism; Catalytic Domain; Cholinesterase Inhibitors/chemistry*; Cholinesterase Inhibitors/metabolism; Echothiophate Iodide/chemistry*; Echothiophate Iodide/metabolism; Hydrolysis; Isoflurophate/chemistry*; Isoflurophate/metabolism; Kinetics; Molecular Dynamics Simulation; Mutation; Paraoxon/chemistry*; Paraoxon/metabolism; Protein Binding; Protein Engineering; Thermodynamics

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