Open AccessEngineering Dynamic Surface Peptide Networks on ButyrylcholinesteraseG117H for Enhanced Organophosphosphorus Anticholinesterase Catalysis
Author(s) -
Kirstin Hester,
Krishna Bhattarai,
Haobo Jiang,
Pratul K. Agarwal,
Carey Pope
Publication year - 2019
Publication title -
chemical research in toxicology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.031
H-Index - 156
eISSN - 1520-5010
pISSN - 0893-228X
DOI - 10.1021/acs.chemrestox.9b00146
Subject(s) - butyrylcholinesterase , catalysis , peptide , chemistry , combinatorial chemistry , biophysics , nanotechnology , organic chemistry , biochemistry , enzyme , materials science , acetylcholinesterase , aché , biology
The single residue mutation of butyrylcholinesterase (BChE G117H ) 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 K M 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.