Structural basis for the oxidation of thiosulfate by a sulfur cycle enzyme

Bamford, Vicki A., Bruno, Stefano, Rasmussen, Tim, Appia-Ayme, Corinne, Cheesman, Myles R., Berks, Ben C. and Hemmings, Andrew M. ORCID: (2002) Structural basis for the oxidation of thiosulfate by a sulfur cycle enzyme. The EMBO Journal, 21. pp. 5599-5610. ISSN 1460-2075

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Reduced inorganic sulfur compounds are utilized by many bacteria as electron donors to photosynthetic or respiratory electron transport chains. This metabolism is a key component of the biogeochemical sulfur cycle. The SoxAX protein is a heterodimeric c-type cytochrome involved in thiosulfate oxidation. The crystal structures of SoxAX from the photosynthetic bacterium Rhodovulum sulfidophilum have been solved at 1.75 Ã… resolution in the oxidized state and at 1.5 Ã… resolution in the dithionite-reduced state, providing the first structural insights into the enzymatic oxidation of thiosulfate. The SoxAX active site contains a haem with unprecedented cysteine persulfide (cysteine sulfane) coordination. This unusual post-translational modification is also seen in sulfurtransferases such as rhodanese. Intriguingly, this enzyme shares further active site characteristics with SoxAX such as an adjacent conserved arginine residue and a strongly positive electrostatic potential. These similarities have allowed us to suggest a catalytic mechanism for enzymatic thiosulfate oxidation. The atomic coordinates and experimental structure factors have been deposited in the PDB with the accession codes 1H31, 1H32 and 1H33.

Item Type: Article
Faculty \ School: Faculty of Science > School of Chemistry
Faculty of Science > School of Biological Sciences
Depositing User: EPrints Services
Date Deposited: 01 Oct 2010 13:37
Last Modified: 24 Oct 2022 03:10
DOI: 10.1093/emboj/cdf566

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