Arylamine N-Acetyltransferase in Mycobacteria

Arylamine N-acetyltransferase (NAT) was first identified in humans for its role in metabolising the anti-tubercular drug isoniazid. Later functional NAT proteins were identified in bacteria including Mycobacterium tuberculosis where they were found to N-acetylate a range of arylamines, hydrazines and hydralazines both in vitro and in vivo. From gene deletion and genomic studies in mycobacteria, it became clear that NAT in Mycobacterium bovis Bacillus Calmette–Guérin (BCG) had an endogenous role in cell-wall metabolism, cholesterol degradation and the nat gene was part of an essential gene cluster for intra-cellular survival of the pathogen M. tuberculosis; this has paved the way for validation of NAT and other proteins encoded in the gene cluster as novel therapeutic targets for anti-tubercular drug design and discovery. This chapter reviews the genomic organisation of the nat gene and the function of the NAT protein in mycobacteria, including the location of the nat gene in the genome. The role of nat and its neighbouring genes, their endogenous substrates and the regulation of their expression in fast-growing environmental and slow-growing pathogenic intra-cellular mycobacteria is also covered