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Download fileTheoretical Studies of Dissociative Phosphoryl Transfer in Interconversion of Phosphoenolpyruvate to Phosphonopyruvate: Solvent Effects, Thio Effects, and Implications for Enzymatic Reactions
journal contribution
posted on 2005-07-21, 00:00 authored by Dingguo Xu, Hua Guo, Yun Liu, Darrin M. YorkThe conversion of phosphoenolpyruvate (PEP) to phosphonopyruvate (P-pyr) is catalyzed by PEP mutase via
a dissociative mechanism. In this work, we investigate the uncatalyzed reaction using ab initio methods,
density functional theory, and the semiempirical MNDO/d method. Comparisons of geometries and relative
energies of stationary points (minima and transition states) with density functional results indicate that the
semiempirical method is reasonably accurate. Solvent effects are examined using implicit solvent models,
including the recently extended smooth conductor-like screening model. Due to the large negative charge
carried by the system, solvation is found to drastically alter the location and energy of stationary points along
the dissociative reaction pathways. The influence of substituting a nonbridging phosphoryl oxygen by sulfur
(thio effects) was also investigated. Implications of these results for the enzymatic reaction are discussed.