Characterization of the mutT nucleoside triphosphatase of Escherichia coli

• Published in: The Journal of biological chemistry Vol. 266; no. 14; pp. 9050 - 9054
• Main Authors: Bhatnagar, S K, Bullions, L C, Bessman, M J
• Format: Journal Article
• Language: English
• Published: United States American Society for Biochemistry and Molecular Biology 15-05-1991
• Subjects: Base Sequence; Binding, Competitive; Deoxyguanine Nucleotides - metabolism; Escherichia coli; Escherichia coli - enzymology; Escherichia coli - genetics; Genes, Bacterial; Molecular Sequence Data; Mutagenesis; Nucleoside-Triphosphatase; Oligonucleotides - chemistry; Oligonucleotides - metabolism; Phosphoric Monoester Hydrolases - antagonists & inhibitors; Phosphoric Monoester Hydrolases - genetics; Phosphoric Monoester Hydrolases - metabolism; Substrate Specificity
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1016/s0021-9258(18)31550-3

The mutT protein, which prevents A:T---C:G transversions during DNA replication, has the following enzymatic properties.
Although it prefers dGTP as a substrate, it hydrolyzes all of the canonical nucleoside triphosphates to some extent. It has
no activity in the absence of divalent cations, is maximally activated by magnesium ions, and has a pH optimum of 9.0. Nucleoside
triphosphates are hydrolyzed according to the following equation. dGTP---dGMP + PPi Studies with nucleotide analogues suggest
that the enzyme may prefer the syn rather than the anti conformation of the nucleoside triphosphates, which might explain
the role it plays in preventing mutations.