2-nitrobenzoate 2-nitroreductase (NbaA) switches its substrate specificity from 2-nitrobenzoic acid to 2,4-dinitrobenzoic acid under oxidizing conditions.

ABSTRACT: 2-Nitrobenzoate 2-nitroreductase (NbaA) of Pseudomonas fluorescens strain KU-7 is a unique enzyme, transforming 2-nitrobenzoic acid (2-NBA) and 2,4-dinitrobenzoic acid (2,4-DNBA) to the 2-hydroxylamine compounds. Sequence comparison reveals that NbaA contains a conserved cysteine residue at position 141 and two variable regions at amino acids 65 to 74 and 193 to 216. The truncated mutant Δ65-74 exhibited markedly reduced activity toward 2,4-DNBA, but its 2-NBA reduction activity was unaffected; however, both activities were abolished in the Δ193-216 mutant, suggesting that these regions are necessary for the catalysis and specificity of NbaA. NbaA showed different lag times for the reduction of 2-NBA and 2,4-DNBA with NADPH, and the reduction of 2,4-DNBA, but not 2-NBA, failed in the prese

SUBMITTER: Kim YH 

PROVIDER: S-EPMC3553833 | biostudies-literature | 2013 Jan

REPOSITORIES: biostudies-literature