1os6
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Cytochrome c7 (PpcA) from Geobacter sulfurreducens
OverviewOverview
The structure of a cytochrome c(7) (PpcA) from Geobacter sulfurreducens, was determined by X-ray diffraction at 1.45 A resolution; the R factor is, 18.2%. The protein contains a three-heme core that is surrounded by 71, amino acid residues. An unusual feature of this cytochrome is that it has, 17 lysine residues, but only nine hydrophobic residues that are larger, than alanine. The details of the structure are described and compared with, those of cytochrome c(7) from Desulfuromonas acetoxidans and with, cytochromes c(3). The two cytochrome c(7) molecules have sequences that, are 46% identical, but the arrangements of the hemes in the two structures, differ; the rms deviation of all alpha-carbons is 2.5 A. These cytochromes, can reduce various metal ions. The reduction site of the chromate ion in, D. acetoxidans is occupied by a sulfate ion in the crystal structure of, PpcA. We identified four additional homologues of cytochrome c(7) in the, G. sulfurreducens genome and three polymers of c(7)-type domains. Of the, polymers, two have four repeats and one has nine repeats. On the basis of, sequence alignments, one of the hemes in each of the cytochrome c(7)-type, domains does not have the bis-histidine coordination. The packing of the, molecules in the crystal structure of PpcA suggests that the polymers have, an elongated conformation and might form a "nanowire".
About this StructureAbout this Structure
1OS6 is a Single protein structure of sequence from Geobacter sulfurreducens with SO4, HEM and DXC as ligands. Full crystallographic information is available from OCA.
ReferenceReference
Family of cytochrome c7-type proteins from Geobacter sulfurreducens: structure of one cytochrome c7 at 1.45 A resolution., Pokkuluri PR, Londer YY, Duke NE, Long WC, Schiffer M, Biochemistry. 2004 Feb 3;43(4):849-59. PMID:14744127
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