Bioinformatic analysis and characterization of the enzyme SE1966 - A putative nitroreductase

Abstract

The Protein Structure Initiative (PSI) was a 15 year, $70 million program with the goal of solving large numbers of protein structures, expanding basic and biomedical research. The initiative added over 5,000 new protein structures, linking them to DNA sequences. While the link between protein structure and DNA sequences is important, the PSI did not provide any functional testing. Adding functional characterization to a solved structure and sequence builds knowledge on how the three are related, accelerating future proteins research and even novel protein design. Our research focuses on analyzing the function of the SE1966 nitroreductase, whose structure was solved by the PSI. Nitroreductases are enzymes that metabolize nitrogen-substituted compounds in bacteria and some eukaryotic enzymes. Nitroreductase enzymes have been used for both environmental and sustainability purposes and show potential in cancer therapeutic treatment. There are more than 24,000 known nitroreductase variants, ordered into 2 families: NfsA and NfsB. Unfortunately, only 20 other enzymes related to NfsA have been investigated, equivalent to less than 1% of the subgroup. Our tests confirm that the nitroreductase is an Flavin Mononucleotide-dependent oxidoreducterase, and indicate a specitivity for NADPH, versus the predicted NADPH/NADH. Characterizing this enzyme adds to general knowledge of how structure and function relate, and specifically, builds understanding of nitroreductase enzymes in environmental and human health.