SER-HIS-ASP catalytic triad in model non-aqueous solvent environment: a computational study.
Emerging new properties and applications of enzymes in organic solvents and ionic liquids are unabating. By applying a combined Quantum Mechanics/Continuum Mechanics computation on a prototypical catalytic triad serine-histidine-aspartate (SER-HIS-ASP) interacting with ethanol or acetonitrile molecules, the major difference between protic and aprotic solvents in effecting transition-state stabilization has been analyzed. Moderately polar aprotic solvent acetonitrile is predicted to be unable to stabilize the transition state in replacing the role of the oxyanion-hole environment, whereas protic ethanol solvent molecules of similar polarity to acetonitrile are adequate in re-gaining the enzymatic activities.
Lau
Justin Kai-Chi
JK
Department of Chemistry, The Hong Kong Baptist University, Waterloo Road, Kowloon Tong, Kowloon, Hong Kong.
Cheng
Yuen-Kit
YK
D000097:Acetonitriles / Q000737:chemistry; D002384:Catalysis; D020134:Catalytic Domain; D019295:Computational Biology; D003198:Computer Simulation; D000431:Ethanol / Q000737:chemistry; D007700:Kinetics; D009842:Oligopeptides / Q000737:chemistry*; D012997:Solvents / Q000737:chemistry*
D000097:Acetonitriles; D009842:Oligopeptides; D012997:Solvents; D000431:Ethanol; C032159:acetonitrile