Rv2985 diadenosine polyphosphatase from M. tuberculosis, an “invasion” enzyme homolog and potential novel antibiotic target

Abstract

The Nudix hydrolases are enzymes that cleave nucleoside diphosphates linked to some moiety, x, and are identified by the common signature sequence: GX5E7REUXEEXGU (U= I, L, or V). We are systematically discovering and characterizing Nudix hydrolases from M. tuberculosis. Rv2985 diadenosine polyphosphatase is a TB homolog to diadenosine polyphosphatases shown to be responsible for the invasiveness of pathogenic bacteria. Rv2985 cleaves Ap4A, Ap5A and Ap6A with nearly comparable activity. Characteristic of Nudix hydrolases, a divalent metal cofactor is required, and Rv2985 has an alkaline pH optimum (pH 8.5). Regardless of which diadenosine polyphosphate is cleaved, ATP is always a resulting product, and it is always the fourth phosphorus from one of the adenosines which is attacked during hydrolysis. Recently we have subcloned and purified a His-tagged protein, and showed that it retains full expression, solubility, and activity, as compared to wild type, and purifies by affinity chromatography as one pure band. Blocking the ability of a pathogen such as M. tuberculosis to be able to invade its human host may be an excellent target for the development of new antibiotics. Supported by an NIH AREA grant.