Elucidation of the metabolic pathway for dibenzothiophene desulphurization by Rhodococcus sp. strain IGTS8 (ATCC 53968)

摘要: Summary: Rhodococcus sp. strain IGTS8 (ATCC 53968) is able to utilize dibenzothiophene (DBT) as a sole source of sulphur. The carbon skeleton DBT not metabolized and conserved 2-hydroxybiphenyl (HBP), which accumulates in the medium. This phenotype due expression plasmid-encoded DBT-desulphurization (dsz) operon, encodes three proteins, DszA, B C. In this paper it shown, using [35S]DBT radiolabelling studies, that sulphur released form inorganic sulphite. pathway desulphurization described detail. summary, DszC catalyses stepwise S-oxidation DBT, first 5-oxide (DBTO) then 5,5-dioxide (DBTO2); DszA conversion DBTO2 2-(2′-hydroxyphenyl)benzene sulphinate (HBPSi-) DszB desulphination HBPSi- give HBP Studies with cell-free extracts show DszC, but DszB, require NADH for activity. 18O2-labelling studies each incorporated oxygen atom derived directly from molecular oxygen. These results are consistent role mono-oxygenase, an apparently unique enzyme reductive hydroxylation leading cleavage thiophene ring, aromatic sulphinic acid hydrolase.