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Crystal structure of oxidized cytochrome c 6A from Arabidopsis thaliana
Author(s) -
Chida Hirotaka,
Yokoyama Takeshi,
Kawai Fumihiro,
Nakazawa Aiko,
Akazaki Hideharu,
Takayama Yasuhiko,
Hirano Takako,
Suruga Kohei,
Satoh Tadashi,
Yamada Seiji,
Kawachi Ryu,
Unzai Satoru,
Nishio Toshiyuki,
Park Sam-Yong,
Oku Tadatake
Publication year - 2006
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/j.febslet.2006.05.067
Subject(s) - cytochrome c , heme , cytochrome , chemistry , cysteine , stereochemistry , cytochrome b , crystal structure , cytochrome c1 , coenzyme q – cytochrome c reductase , cytochrome f , arabidopsis thaliana , amino acid , crystallography , biochemistry , mutant , mitochondrion , chloroplast , gene , enzyme , mitochondrial dna , photosystem i
Compared with algal and cyanobacterial cytochrome c 6 , cytochrome c 6A from higher plants contains an additional loop of 12 amino acid residues. We have determined the first crystal structure of cytochrome c 6A from Arabidopsis thaliana at 1.5 Å resolution in order to help elucidate its function. The overall structure of cytochrome c 6A follows the topology of class I c ‐type cytochromes in which the heme prosthetic group covalently binds to Cys16 and Cys19, and the iron has octahedral coordination with His20 and Met60 as the axial ligands. Two cysteine residues (Cys67 and Cys73) within the characteristic 12 amino acids loop form a disulfide bond, contributing to the structural stability of cytochrome c 6A . Our model provides a chemical basis for the known low redox potential of cytochrome c 6A which makes it an unsuitable electron carrier between cytochrome b 6 f and PSI.