An exchange of single amino acid between the phosphohydrolase modules of Escherichia coli MutT and Mycobacterium smegmatis MutT1 switches their cleavage specificities

Emam, EAF and Roy, K and Varshney, U (2024) An exchange of single amino acid between the phosphohydrolase modules of Escherichia coli MutT and Mycobacterium smegmatis MutT1 switches their cleavage specificities. In: DNA Repair, 139 .

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Abstract

MutT proteins belong to the Nudix hydrolase superfamily that includes a diverse group of Mg2+ requiring enzymes. These proteins use a generalized substrate, nucleoside diphosphate linked to a chemical group X (NDP-X), to produce nucleoside monophosphate (NMP) and the moiety X linked with phosphate (XP). E. coli MutT (EcoMutT) and mycobacterial MutT1 (MsmMutT1) belong to the Nudix hydrolase superfamily that utilize 8-oxo-(d)GTP (referring to both 8-oxo-GTP or 8-oxo-dGTP). However, predominant products of their activities are different. While EcoMutT produces 8-oxo-(d)GMP, MsmMutT1 gives rise to 8-oxo-(d)GDP. Here, we show that the altered cleavage specificities of the two proteins are largely a consequence of the variation at the equivalent of Gly37 (G37) in EcoMutT to Lys (K65) in the MsmMutT1. Remarkably, mutations of G37K (EcoMutT) and K65G (MsmMutT1) switch their cleavage specificities to produce 8-oxo-(d)GDP, and 8-oxo-(d)GMP, respectively. Further, a time course analysis using 8-oxo-GTP suggests that MsmMutT1(K65G) hydrolyses 8-oxo-(d)GTP to 8-oxo-(d)GMP in a two-step reaction via 8-oxo-(d)GDP intermediate. Expectedly, unlike EcoMutT (G37K) and MsmMutT1, EcoMutT and MsmMutT1 (K65G) rescue an E. coli �mutT strain, better by decreasing A to C mutations. © 2024 Elsevier B.V.

Item Type:	Journal Article
Publication:	DNA Repair
Publisher:	Elsevier B.V.
Additional Information:	The copyright for this article belongs to Elsevier B.V.
Department/Centre:	Division of Biological Sciences > Microbiology & Cell Biology
Date Deposited:	28 Jul 2024 16:56
Last Modified:	28 Jul 2024 16:56
URI:	http://eprints.iisc.ac.in/id/eprint/85175

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