1dw3
STRUCTURE OF A REDUCED OXYGEN BINDING CYTOCHROME C
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OverviewOverview
The 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.
About this StructureAbout this Structure
1DW3 is a Single protein structure of sequence from Rhodobacter sphaeroides with HEM as ligand. Full crystallographic information is available from OCA.
ReferenceReference
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
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