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c7-type three-heme cytochrome domainc7-type three-heme cytochrome domain
Structural highlights
FunctionEvolutionary 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 structure of a novel c(7)-type cytochrome domain that has two bishistidine coordinated hemes and one heme with histidine, methionine coordination (where the sixth ligand is a methionine residue) was determined at 1.7 A resolution. This domain is a representative of domains that form three polymers encoded by the Geobacter sulfurreducens genome. Two of these polymers consist of four and one protein of nine c(7)-type domains with a total of 12 and 27 hemes, respectively. Four individual domains (termed A, B, C, and D) from one such multiheme cytochrome c (ORF03300) were cloned and expressed in Escherichia coli. The domain C produced diffraction quality crystals from 2.4 M sodium malonate (pH 7). The structure was solved by MAD method and refined to an R-factor of 19.5% and R-free of 21.8%. Unlike the two c(7) molecules with known structures, one from G. sulfurreducens (PpcA) and one from Desulfuromonas acetoxidans where all three hemes are bishistidine coordinated, this domain contains a heme which is coordinated by a methionine and a histidine residue. As a result, the corresponding heme could have a higher potential than the other two hemes. The apparent midpoint reduction potential, E(app), of domain C is -105 mV, 50 mV higher than that of PpcA. Structure of a novel c7-type three-heme cytochrome domain from a multidomain cytochrome c polymer.,Pokkuluri PR, Londer YY, Duke NE, Erickson J, Pessanha M, Salgueiro CA, Schiffer M Protein Sci. 2004 Jun;13(6):1684-92. Epub 2004 May 7. PMID:15133162[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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