Characterization and mutational analysis of an exopolyphosphatase from Mycobacterium smegmatis

Abstract

Inorganic polyphosphate (poly-P) is a linear polymer comprising tens to hundreds of orthophosphate residues linked by ‘high-energy' phosphoanhydride bonds. These bio-polymers are found within all living cells, and have been shown to have a wide variety of important physiological functions. In most bacteria, the hydrolysis of Poly-P chains to monophosphate is predominantly mediated by exopolyphosphatase (Ppx) enzymes. However many bacterial species, lack identifiable Ppx enzymes. Mycobacterium smegmatis, an important model organism for tuberculosis-related experimental systems, lacks an identifiable Ppx protein, but encodes a protein sharing homology with both guanosine pentaphosphate hydrolase and Ppx enzymes (Msmeg_5413) ...