X-Ray Structure of a Self-Compartmentalizing Sulfur Cycle Metalloenzyme
Urich, T., Gomes, C.M., Kletzin, A., Frazao, C.(2006) Science 311: 996
- PubMed: 16484493 
- DOI: https://doi.org/10.1126/science.1120306
- Primary Citation of Related Structures:  
2CB2 - PubMed Abstract: 
Numerous microorganisms oxidize sulfur for energy conservation and contribute to the global biogeochemical sulfur cycle. We have determined the 1.7 angstrom-resolution structure of the sulfur oxygenase reductase from the thermoacidophilic archaeon Acidianus ambivalens, which catalyzes an oxygen-dependent disproportionation of elemental sulfur. Twenty-four monomers form a large hollow sphere enclosing a positively charged nanocompartment. Apolar channels provide access for linear sulfur species. A cysteine persulfide and a low-potential mononuclear non-heme iron site ligated by a 2-His-1-carboxylate facial triad in a pocket of each subunit constitute the active sites, accessible from the inside of the sphere. The iron is likely the site of both sulfur oxidation and sulfur reduction.
Organizational Affiliation: 
Darmstadt University of Technology, Institute of Microbiology and Genetics, Schnittspahnstrasse 10, 64287 Darmstadt, Germany.