title: Cloning and sequence analysis of the gene encoding Methylophilus methylotrophus cytochrome c", a unique protein with a perpendicular orientation of the histidinyl ligands.
abstract: Cytochrome c" from Methylophilus methylotrophus is an unusual monohaem protein that undergoes a major redox-linked spin-state transition: one of the two axial histidines bound to the iron in the oxidised form is detached upon reduction and a proton is taken up. A 3.5-kb DNA fragment, containing the gene encoding cytochrome c" (cycA), has been cloned and sequenced. The cytochrome c" gene codes for a pre-protein with a typical prokaryotic 20-residue signal sequence, suggesting that the protein is synthesised as a precursor which is processed during its secretion into the periplasm. The C-terminus of cytochrome c" has homology with the corresponding region of an oxygen-binding haem protein (SHP) from phototrophically grown Rhodobacter sphaeroides. SHP is similar in size and in the location of its haem-binding site. Immediately downstream from cytochrome c" a second open reading frame (ORF) codes for a 23-kDa protein with similarity to the cytochrome b-type subunit of Ni-Fe hydrogenase. The possibility of coordinated expression of cycA and this ORF is discussed.
authors.affiliation: Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Oeiras, Portugal.
authors.forename: N J
authors.initials: NJ
authors.lastname: Price
authors.forename: E
authors.initials: E
authors.lastname: Vijgenboom
authors.forename: G
authors.initials: G
authors.lastname: Ribeiro
authors.forename: J V
authors.initials: JV
authors.lastname: Costa
authors.forename: G W
authors.initials: GW
authors.lastname: Canters
authors.forename: H
authors.initials: H
authors.lastname: Santos
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D003001:Cloning, Molecular; D003574:Cytochrome c Group / Q000737:chemistry / Q000235:genetics*; D016373:DNA, Antisense / Q000737:chemistry; D004269:DNA, Bacterial / Q000737:chemistry; D005798:Genes, Bacterial; D006088:Gram-Negative Aerobic Bacteria / Q000235:genetics*; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D009876:Operon; D016415:Sequence Alignment
chemical_list: D003574:Cytochrome c Group; D016373:DNA, Antisense; D004269:DNA, Bacterial; C076615:cytochrome c''