1H31

Oxidised SoxAX complex from Rhodovulum sulfidophilum

Summary for 1H31

• Entry DOI: 10.2210/pdb1h31/pdb
• Descriptor: DIHEME CYTOCHROME C, CYTOCHROME C, HEME C, ... (4 entities in total)
• Functional Keywords: electron transport, sulfur cycle, soxax complex, thiosulfate oxidation, cysteine persulfide heme ligand
• Biological source: RHODOVULUM SULFIDOPHILUM; More
• Total number of polymer chains: 8
• Total formula weight: 182346.66

Authors

Bamford, V.A.,Bruno, S.,Rasmussen, T.,Appia-Ayme, C.,Cheesman, M.R.,Berks, B.C.,Hemmings, A.M. (deposition date: 2002-08-21, release date: 2002-11-07, Last modification date: 2024-11-13)

Primary citation

Bamford, V.A.,Bruno, S.,Rasmussen, T.,Appia-Ayme, C.,Cheesman, M.R.,Berks, B.C.,Hemmings, A.M.
Structural Basis for the Oxidation of Thiosulfate by a Sulfur Cycle Enzyme
Embo J., 21:5599-, 2002

PubMed Abstract: 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 A resolution in the oxidized state and at 1.5 A 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.

PubMed: 12411478
DOI: 10.1093/EMBOJ/CDF566

Experimental method

X-RAY DIFFRACTION (2.55 Å)