Asp is not a strong nucleophile, and coordination to zinc will make it less so. It is more likely that a zinc-bound water is acting as a nucleophile. If there is no observed water attached to your Zn, consider the possibility of ligand-water exchange, as in bacterial beta-carbonic anhydrases.
Roger Rowlett On Jul 20, 2012 1:31 AM, "Crystal Xu" <crystalh...@gmail.com> wrote: > Hi everyone, > > I am studying the catalytic mechanism of an enzyme. My structural data > indicates that an Asp is of most possibility to sever as a general base. > The Asp residue is coordinated to a zinc ion. Would it be possible that the > side-chain > carboxyl group of Asp attacks a carbon atom of the substrate? Does anyone > know any examples? > > Thanks very much. > > Best regards. > > >
