title: Characterization of an oxidoreductase from the arylamine N-acetyltransferase operon in Mycobacterium smegmatis.
abstract: Mycobacterium tuberculosis, the most successful bacterial pathogen, causes tuberculosis, a disease that still causes more than 2 million deaths per year. Arylamine N-acetyltransferase is an enzyme that is conserved in most Mycobacterium spp. The nat gene belongs to an operon that is important for the intracellular survival of M. tuberculosis within macrophages. The nat operon in Mycobacterium smegmatis and other fast-growing mycobacterial species has a unique organization containing genes with uncharacterized function. Here, we describe the biochemical, biophysical and structural characterization of the MSMEG_0308 gene product (MS0308) of the M. smegmatis nat operon. While characterizing the function of MS0308, we validated the oxidoreductase property; however, we found that the enzyme was not utilizing dihydrofolate as its substrate, hence we first report that MS0308 is not a dihydrofolate reductase, as annotated in the genome. The structure of this oxidoreductase was solved at 2.0 Å in complex with the cofactor NADPH and has revealed the hydrophobic pocket where the endogenous substrate binds.
authors.affiliation: Department of Biological Sciences, Institute of Structural and Molecular Biology, Birkbeck College, University of London, London, UK.
authors.forename: Dimitrios
authors.initials: D
authors.lastname: Evangelopoulos
authors.forename: Nora
authors.initials: N
authors.lastname: Cronin
authors.forename: Tina
authors.initials: T
authors.lastname: Daviter
authors.forename: Edith
authors.initials: E
authors.lastname: Sim
authors.forename: Nicholas H
authors.initials: NH
authors.lastname: Keep
authors.forename: Sanjib
authors.initials: S
authors.lastname: Bhakta
mesh_terms: D001191:Arylamine N-Acetyltransferase / Q000737:chemistry / Q000235:genetics*; D018360:Crystallography, X-Ray; D006801:Humans; D008958:Models, Molecular; D020102:Mycobacterium smegmatis / Q000201:enzymology; D009249:NADP / Q000378:metabolism; D009876:Operon; D010088:Oxidoreductases / Q000235:genetics* / Q000378:metabolism; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D013762:Tetrahydrofolate Dehydrogenase / Q000378:metabolism
chemical_list: D011994:Recombinant Proteins; D009249:NADP; D010088:Oxidoreductases; D013762:Tetrahydrofolate Dehydrogenase; D001191:Arylamine N-Acetyltransferase