title: Crystal structure of low-potential cytochrome c549 from Synechocystis sp. PCC 6803 at 1.21 A resolution.
abstract: The crystal structure of low-potential cytochrome c549, an extrinsic component of the photosystem II (PS II) from Synechocystis sp. PCC 6803, was obtained directly from single-wavelength 1.21 A resolution diffraction data. This is the first monodomain bis-histidinyl monoheme cytochrome c to be structurally characterized. The extended N-terminal region of c549 builds up a two-strand antiparallel beta-sheet in a hairpin motif, which extends through two molecules owing to crystal packing. Both peptide termini are involved in crystal contacts, which may explain their protrusion out of the globular fold. The C-terminus is preceded by a 9 A-long hydrophobic finger extending from a positively charged base and could be involved in PSII interactions, as well as a protruding negative patch built by a set of conserved acidic residues among c549 sequences.
authors: Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, 2781-901 Oeiras, Portugal.
authors: C
authors: C
authors: Frazão
authors: F J
authors: FJ
authors: Enguita
authors: R
authors: R
authors: Coelho
authors: G M
authors: GM
authors: Sheldrick
authors: J A
authors: JA
authors: Navarro
authors: M
authors: M
authors: Hervás
authors: M A
authors: MA
authors: De la Rosa
authors: M A
authors: MA
authors: Carrondo
mesh_terms: D000595:Amino Acid Sequence; D018360:Crystallography, X-Ray; D000458:Cyanobacteria / Q000201:enzymology*; D003574:Cytochrome c Group / Q000737:chemistry*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010802:Phylogeny; D011487:Protein Conformation; D017386:Sequence Homology, Amino Acid
chemical_list: D003574:Cytochrome c Group; C024104:cytochrome c-555,549