title: Cytochrome c-554 from Methylosinus trichosporium OB3b; a protein that belongs to the cytochrome c2 family and exhibits a HALS-Type EPR signal.
abstract: A small soluble cytochrome c-554 purified from Methylosinus trichosporium OB3b has been purified and analyzed by amino acid sequencing, mass spectrometry, visible, CD and EPR spectroscopies. It is found to be a mono heme protein with a characteristic cytochrome c fold, thus fitting into the class of cytochrome c(2), which is the bacterial homologue of mitochondrial cytochrome c. The heme iron has a Histidine/Methionine axial ligation and exhibits a highly anisotropic/axial low spin (HALS) EPR signal, with a g(max) at 3.40, and ligand field parameters V/ξ = 0.99, Δ/ξ = 4.57. This gives the rhombicity V/Δ = 0.22. The structural basis for this HALS EPR signal in Histidine/Methionine ligated hemes is not resolved. The ligand field parameters observed for cytochrome c-554 fits the observed pattern for other cytochromes with similar ligation and EPR behaviour.
authors.affiliation: Department of Molecular Biosciences, University of Oslo, Oslo, Norway.
authors.forename: Espen
authors.initials: E
authors.lastname: Harbitz
authors.forename: K Kristoffer
authors.initials: KK
authors.lastname: Andersson
mesh_terms: D000042:Absorption; D000595:Amino Acid Sequence; D000818:Animals; D016880:Anisotropy; D001426:Bacterial Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D002942:Circular Dichroism; D003573:Cytochrome b Group / Q000378:metabolism; D003574:Cytochrome c Group / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D045362:Cytochromes c2 / Q000378:metabolism*; D004578:Electron Spin Resonance Spectroscopy; D006418:Heme / Q000378:metabolism; D006736:Horses; D013058:Mass Spectrometry; D008715:Methionine / Q000378:metabolism; D020619:Methylococcus capsulatus / Q000378:metabolism; D020602:Methylosinus trichosporium / Q000378:metabolism*; D008969:Molecular Sequence Data; D008970:Molecular Weight; D013113:Spin Labels; D040681:Structural Homology, Protein
chemical_list: D001426:Bacterial Proteins; D003573:Cytochrome b Group; D003574:Cytochrome c Group; D013113:Spin Labels; D006418:Heme; C048756:cytochrome b 555; D045362:Cytochromes c2; C022302:cytochrome C-552; D008715:Methionine