1e0c
From Proteopedia
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SULFURTRANSFERASE FROM AZOTOBACTER VINELANDII
Overview
Rhodanese is an ubiquitous enzyme that in vitro catalyses the transfer of, a sulfur atom from suitable donors to nucleophilic acceptors by way of a, double displacement mechanism. During the catalytic process the enzyme, cycles between a sulfur-free and a persulfide-containing form, via, formation of a persulfide linkage to a catalytic Cys residue. In the, nitrogen-fixing bacteria Azotobacter vinelandii the rhdA gene has been, identified and the encoded protein functionally characterized as a, rhodanese. The crystal structure of the A. vinelandii rhodanese has been, determined and refined at 1.8 A resolution in the sulfur-free and, persulfide-containing forms. Conservation of the overall three-dimensional, fold of bovine rhodanese is observed, with substantial modifications of, the protein structure in the proximity of the catalytic residue Cys230., Remarkably, the native enzyme is found as the Cys230-persulfide form; in, the sulfur-free state the catalytic Cys residue adopts two alternate, conformations, reflected by perturbation of the neighboring active-site, residues, which is associated with a partly reversible loss of, thiosulfate:cyanide sulfurtransferase activity. The catalytic mechanism of, A. vinelandii rhodanese relies primarily on the main-chain conformation of, the 230 to 235 active-site loop and on a surrounding strong positive, electrostatic field. Substrate recognition is based on residues which are, entirely different in the prokaryotic and eukaryotic enzymes. The, active-site loop of A. vinelandii rhodanese displays striking structural, similarity to the active-site loop of the similarly folded catalytic, domain of dual specific phosphatase Cdc25, suggesting a common, evolutionary origin of the two enzyme families.
About this Structure
1E0C is a Single protein structure of sequence from Azotobacter vinelandii with SO4, MG and EDO as ligands. Active as Thiosulfate sulfurtransferase, with EC number 2.8.1.1 Known structural/functional Site: . Full crystallographic information is available from OCA.
Reference
The crystal structure of a sulfurtransferase from Azotobacter vinelandii highlights the evolutionary relationship between the rhodanese and phosphatase enzyme families., Bordo D, Deriu D, Colnaghi R, Carpen A, Pagani S, Bolognesi M, J Mol Biol. 2000 May 12;298(4):691-704. PMID:10788330
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