Intermolecular interaction study of dissimilatory sulfite reductase (DsrAB) from sulfur oxidizing proteobacteria allchromatium vinosum

Abstract

Dissimilatory Sulfite Reductase (dSiR) is the main redox enzyme system utilized in sulfur metabolism in both sulfur oxidizing and reducing prokaryotes. Anoxygenic phototrophic bacteria Allochromatium vinosum produces elemental sulfur during sulfur cycle which is ultimately oxidized sulfate by DSR operon. Allochromatium vinosum encodes dsrAB reverse dSiR that oxidizes thiosulfate or elemental sulfur. DsrAB is a α2β2 hetero-tetrameric complex. In our present study, we first reported the three dimensional structure of DsrAB protein complex from Allochromatium vinosum and we also predicted the protein-protein interactions between DsrA and DsrB proteins. DsrAB is a major redox enzyme complex required in both sulfur oxidation and reduction processes so this structure function relationship investigation will help in researches to predict the biochemical mechanism of sulfur-oxidation. The importance of the study lies in the fact that sulfur metabolism pathways are used in waste remediation and bio-hydrogen production. This is the most important aspect of our analysis.