A new paradigm for electrostatic catalysis of radical reactions in vitamin B12 enzymes.

ABSTRACT: The catalytic power of enzymes containing coenzyme B(12) cofactor has been, in some respects, the "last bastion" for the strain hypothesis. The present work explores the origin of this effect by using simulation methods that overcome the sampling difficulties of previous energy minimization studies. It is found that the major part of the catalytic effect is due to the electrostatic interaction between the ribose and the protein, and that the strain contribution is very small. Remarkably, enzymes can use electrostatic effects even in a radical process, when the charge distribution of the reacting fragments does not change significantly during the reaction. Electrostatic catalysis can, in such cases, be obtained by attaching a polar group to the leaving fragment and designing an active site

SUBMITTER: Sharma PK 

PROVIDER: S-EPMC1887576 | biostudies-literature | 2007 Jun

REPOSITORIES: biostudies-literature