Visualization of mutagenic nucleotide processing by Escherichia coli MutT, a Nudix hydrolase

Abstract

Significance Time-resolved X-ray crystallography has captured transient elements in enzymatic reactions and has advanced understanding regarding canonical mechanisms. Although Nudix hydrolases are involved in cellular metabolism via hydrolytic activities, the catalytic mechanisms remain elusive. This is because the Nudix hydrolases are defined only by a highly conserved short motif and because most mechanisms are based on the structures mimicking the reaction states. Time-resolved X-ray crystallography of MutT has followed the course of 8-oxo-dGTP hydrolysis and enabled visualization of the process of nucleophilic substitution by a water molecule that is synchronized with the sequential coordination of three metal ions. These observations are consistent with previous kinetic analysis and are indicative of a three-metal-ion mechanism.