A kinetic analysis of three modified novel nitroreductases

Abstract

A kinetic comparison between three nitroreductase enzymes isolated from the genome of Bacillus licheniformis ATCC 14580 for prospective use as immobilised enzymes for explosives detection has been conducted. The genes encoding the three enzymes (yfkO [BLNfnB] encoding an NfsB-like enzyme; nfrA [BLNfrA1] and ycnD [BLNfrA2] encoding PnrA-like enzymes) have been PCR amplified from the native genome and cloned into pET-28a(+) and a modified cysteine((6))-tagged pET-28a(+) and subsequently over-expressed, purified, and biochemically characterised. The previously uncharacterised nitroreductases exhibited activity against a wide range of explosives, including cyclic nitramines. Amino acid alignments and overall structural comparisons with other nitroreductase family members suggest that the B. licheniformis enzymes are members of the NfsA-Frp/NfsB-FRase I family group. Despite the overall low amino acid identity, regions for flavin mononucleotide binding and active site residues were highly conserved.

Development of a novel enzymatic biosensor based on an ion-selective field effect transistor for the detection of explosives

“…However, in contrast to the results obtained by Gwenin et al, no enzymatic activity was detected toward non-aromatic compounds such as HMX, RDX, and nitroglycerine. However, three enzymes belonging to the NTR family, cloned from Bacillus licheniformis, are not active against non-aromatic nitro compounds [23]. The substrate specificity profiles for different enzymes from different sources indicated that NTRs could be used for the detection of not only TNT and tetryl, but also other explosive materials.…”

Who will attack the nitroaromatics first? The enzymatic diversity and conservation

“…Type II enzymes catalyse single-electron transfer to produce a nitro anion radical, which can reduce nitro group to a nitroso group. Under aerobic conditions, however, the nitro anion radical reacts with oxygen and produces superoxide anion in a futile cycle 20 .…”

The Role of Nitroreductases in Resistance to Nitroimidazoles

“…Nitroreductases (NTR) are a family of proteins involved in the reduction of nitro-containing compounds [ 1 ]. The flexibility of these enzymes comprises their usefulness in a variety of biological and medical applications.…”