Confers resistance to antitubercular drugs benzothiazinone (BTZ) and dinitrobenzamide (DNB). Inactivates BTZ and DNB by reducing an essential nitro group of these compounds to amino group or to hydroxyl amine, respectively, using NADH or NADPH as source of reducing equivalents; two electrons are transferred (PubMed:22069462, PubMed:20624223). Able to reduce the nitro group of bicyclic nitroimidazole PA-824, but not of quinone menadione, nitrofurazone, methyl-4-nitrobenzoate, 4-nitrobenzene methyl sulfonate or 4-nitroacetophenone (PubMed:20624223). Binds 1 FMN per subunit. Optimum pH is 7.5 to 9.0. Homodimer. Transcriptionally repressed by MSMEG_6503/MSMEI_6332. Loss of resistance to antitubercular drug BTZ043, but still resistant to PA-824. Potentially helps in the design of second generation BTZ and DNB drugs that are less susceptible to nitroreduction. Belongs to the nitroreductase family. Truncated N-terminus.