Thiosulfate dehydrogenase (TsdA) from Allochromatium vinosum: structural and functional insights into thiosulfate oxidation.

ABSTRACT: Although the oxidative condensation of two thiosulfate anions to tetrathionate constitutes a well documented and significant part of the natural sulfur cycle, little is known about the enzymes catalyzing this reaction. In the purple sulfur bacterium Allochromatium vinosum, the reaction is catalyzed by the periplasmic diheme c-type cytochrome thiosulfate dehydrogenase (TsdA). Here, we report the crystal structure of the "as isolated" form of A. vinosum TsdA to 1.98 Å resolution and those of several redox states of the enzyme to different resolutions. The protein contains two typical class I c-type cytochrome domains wrapped around two hemes axially coordinated by His(53)/Cys(96) and His(164)/Lys(208). These domains are very similar, suggesting a gene duplication event during evolution. A li

SUBMITTER: Brito JA 

PROVIDER: S-EPMC4423707 | biostudies-literature | 2015 Apr

REPOSITORIES: biostudies-literature