1dw0
From Proteopedia
STRUCTURE OF OXIDIZED SHP, AN OXYGEN BINDING CYTOCHROME C
Structural highlights
FunctionSHP_CERS4 High-spin cytochrome. Transiently bind oxygen during autoxidation, which occurs with a half-life of 3 minutes with a 4-fold excess of O(2). Also binds carbon monoxide, azide and cyanide. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedThe photosynthetic bacterium Rhodobacter sphaeroides produces a heme protein (SHP), which is an unusual c-type cytochrome capable of transiently binding oxygen during autooxidation. Similar proteins have not only been observed in other photosynthetic bacteria but also in the obligate methylotroph Methylophilus methylotrophus and the metal reducing bacterium Shewanella putrefaciens. A three-dimensional structure of SHP was derived using the multiple isomorphous replacement phasing method. Besides a model for the oxidized state (to 1.82 A resolution), models for the reduced state (2.1 A resolution), the oxidized molecule liganded with cyanide (1. 90 A resolution), and the reduced molecule liganded with nitric oxide (2.20 A resolution) could be derived. The SHP structure represents a new variation of the class I cytochrome c fold. The oxidized state reveals a novel sixth heme ligand, Asn(88), which moves away from the iron upon reduction or when small molecules bind. The distal side of the heme has a striking resemblance to other heme proteins that bind gaseous compounds. In SHP the liberated amide group of Asn(88) stabilizes solvent-shielded ligands through a hydrogen bond. Crystal structures of an oxygen-binding cytochrome c from Rhodobacter sphaeroides.,Leys D, Backers K, Meyer TE, Hagen WR, Cusanovich MA, Van Beeumen JJ J Biol Chem. 2000 May 26;275(21):16050-6. PMID:10821858[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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