Biosynthesis and recycling of nicotinamide cofactors in mycobacterium tuberculosis. An essential role for NAD in nonreplicating bacilli.

ABSTRACT: Despite the presence of genes that apparently encode NAD salvage-specific enzymes in its genome, it has been previously thought that Mycobacterium tuberculosis can only synthesize NAD de novo. Transcriptional analysis of the de novo synthesis and putative salvage pathway genes revealed an up-regulation of the salvage pathway genes in vivo and in vitro under conditions of hypoxia. [14C]Nicotinamide incorporation assays in M. tuberculosis isolated directly from the lungs of infected mice or from infected macrophages revealed that incorporation of exogenous nicotinamide was very efficient in in vivo-adapted cells, in contrast to cells grown aerobically in vitro. Two putative nicotinic acid phosphoribosyltransferases, PncB1 (Rv1330c) and PncB2 (Rv0573c), were examined by a combination of in vi

SUBMITTER: Boshoff HI 

PROVIDER: S-EPMC2443648 | biostudies-literature | 2008 Jul

REPOSITORIES: biostudies-literature