title: Dibenzothiophene desulfurizing enzymes from moderately thermophilic bacterium Bacillus subtilis WU-S2B: purification, characterization and overexpression.
abstract: The moderately thermophilic bacterium Bacillus subtilis WU-S2B desulfurized dibenzothiophene (DBT) at 50 degrees C through the selective cleavage of carbon-sulfur bonds. In this study, three enzymes involved in the microbial DBT desulfurization were purified and characterized. The first two enzymes, DBT monooxygenase (BdsC) and DBT sulfone monooxygenase (BdsA), were purified from the wild-type strain, and the last one, 2'-hydroxybiphenyl 2-sulfinic acid desulfinase (BdsB), was purified from the recombinant Escherichia coli overexpressing the gene, bdsB, with chaperonin genes, groEL/ES. The genes of BdsC and BdsA were also overexpressed. The molecular weights of BdsC and BdsA were determined to be 200 and 174 kDa, respectively, by gel filtration chromatography, suggesting that both enzymes had four identical subunits. BdsB had a monomeric structure of 40 kDa. The three enzymes were characterized and compared with the corresponding enzymes (DszC, DszA, and DszB) of mesophilic desulfurization bacteria. The specific activities of BdsC, BdsA, and BdsB were 84.2, 855, and 280 units/mg, respectively, and the latter two activities were higher than those of DszA and DszB. The heat stability and optimum temperature of BdsC, BdsA, and BdsB were higher than those of DszC, DszA, and DszB. Other enzymatic properties were investigated in detail.
authors.affiliation: Department of Biotechnology, Tottori University, 4-101 Koyamacho-minami, Tottori 680-8552, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Ohshiro
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Ishii
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Matsubara
authors.forename: Koichi
authors.initials: K
authors.lastname: Ueda
authors.forename: Yoshikazu
authors.initials: Y
authors.lastname: Izumi
authors.forename: Kuniki
authors.initials: K
authors.lastname: Kino
authors.forename: Kohtaro
authors.initials: K
authors.lastname: Kirimura
mesh_terms: D001412:Bacillus subtilis / Q000201:enzymology*; D001709:Biotechnology / Q000379:methods*; D004795:Enzyme Stability; D006863:Hydrogen-Ion Concentration; D010088:Oxidoreductases / Q000096:biosynthesis* / Q000737:chemistry* / Q000302:isolation & purification; D010105:Oxygenases / Q000096:biosynthesis / Q000737:chemistry / Q000302:isolation & purification; D013379:Substrate Specificity; D013696:Temperature; D013876:Thiophenes / Q000378:metabolism*; D015533:Transcriptional Activation
chemical_list: D013876:Thiophenes; D010088:Oxidoreductases; D010105:Oxygenases; C421210:dibenzothiophene sulfone monooxygenase; C090100:dibenzothiophene monooxygenase; C016366:dibenzothiophene