Homology Modeling and In Silico Docking Studies of DszC Enzyme of Streptomyces sp. VUR PPR 101

Abstract

Sulfur dioxide released during the combustion of fossil fuels causes hazardous effects to living beings. The traditional hydrodesulfurization (HDS) which is employed to remove sulfur components from fossil fuels is not effective in the reduction in aromatic organosulfur compounds like benzothiophene (BT), dibenzothiophene (DBT) and its derivatives. Biodesulfurization process by microorganisms is considered as an effective one over HDS in the removal of sulfur from fuels. DBT, which is a typical recalcitrant organosulfur compound, is considered as a model compound for biodesulfurization studies. Microbes which employ 4S pathway for the removal of sulfur from DBT are commercially so significant. The 4S pathway encompasses four reactions involving three enzymes. The present work deals with the DszC enzyme which catalyzes the first two reaction steps of 4S pathway. The 3D structure of DszC enzyme protein of Streptomyces sp. VUR PPR 101 was modeled and validated. Four mutant DszC enzyme proteins viz., Q119I, H221L, F161A and N129A, were constructed. Wild and mutant DszC proteins were docked against the substrates, DBT and dibenzothiophene sulfoxide (DBTO). Based on the Libdock scores of the docked complexes, the mutant proteins F161A and H221L were found with the highest affinity toward DBT and DBTO, respectively.