Crystallization and preliminary X-ray analysis of Escherichia coli MutT in binary and ternary complex forms.

Abstract

During replication, Escherichia coli MutT prevents the misincorporation of mutagenic 8-oxoguanine into nascent DNA strands opposite adenine by hydrolyzing 8-oxo-dGTP in nucleotide pools to 8-oxo-dGMP. E. coli MutT is the most widely investigated member of the Nudix hydrolase family, which is large and found in all organisms. By co-crystallization of MutT with 8-oxo-dGMP, a reaction product, crystals of the binary complex were obtained using ammonium sulfate as a precipitant. The crystals belong to space group P2(1)2(1)2(1), with unit-cell parameters a = 37.9, b = 56.0, c = 59.4 A. Assuming the presence of one protein-nucleotide complex in the asymmetric unit, the Matthews coefficient V(M) is 2.1 A(3) Da(-1). Crystals of the ternary complex were prepared by soaking crystals of the binary complex in 1 mM MnCl(2) solution. They diffracted to 1.96 and 2.56 A resolution, respectively.