Theoretical insights into the mechanism of acetylcholinesterase-catalyzed acylation of acetylcholine.
Acylation of acetylcholine (ACh) catalyzed by acetylcholinesterase (AChE) has been studied using high-level theoretical calculations on a model system that mimics the reaction center of the enzyme, and compared with uncatalyzed acylation reaction. The geometries of all the intermediates and transition states, activation energies, and solvent effects have been calculated. The calculations predict simultaneous formation of two short-strong hydrogen bonds (SSHB) in the rate-determining transition state structures [the first SSHB involves the hydrogen atom of Ser-200 (H(s)) and another involves the hydrogen atom of His-440 (H(h))]. In the intermediate states, the H-bond corresponding to H(h) involves SSHB, whereas the one corresponding to H(s) does not.
Manojkumar
T K
TK
Creative Research Initiative Center for Superfunctional Materials, Department of Chemistry, Division of Molecular and Life Sciences, Pohang University of Science and Technology, San 31, Hyojadong, Namgu, Pohang 790-784, Korea.
Cui
Chunzhi
C
Kim
Kwang S
KS
D000109:Acetylcholine / Q000737:chemistry*; D000110:Acetylcholinesterase / Q000737:chemistry / Q000378:metabolism*; D000215:Acylation; D002384:Catalysis; D006860:Hydrogen Bonding; D008962:Models, Theoretical; D013816:Thermodynamics
D000110:Acetylcholinesterase; D000109:Acetylcholine