Cytochrome c family

The CXXCH heme binding motif in cytochrome c proteins. Amino acid side chains are shown in white and heme is colored black.

Cytochromes c (cyt c, c-type cytochromes) cytochromes, or heme-containing proteins, that have heme C covalently attached to the peptide backbone via one or two thioether bonds.[1] These bonds are in most cases part of a specific Cys-X-X-Cys-His (CXXCH) binding motif, where X denotes a miscellaneous amino acid. Two thioether bonds of cysteine residues bind to the vinyl sidechains of heme, and the histidine residue coordinates one axial binding site of the heme iron. Less common binding motifs can include a single thioether linkage,[2] a lysine[3] or a methionine[4] instead of the axial histidine or a CXnCH binding motif with n>2.[5] The second axial site of the iron can be coordinated by amino acids of the protein,[6] substrate molecules or water. Cytochromes c possess a wide range of properties and function as electron transfer proteins or catalyse chemical reactions involving redox processes.[7] A prominent member of this family is mitochondrial cytochrome c.

  1. ^ "Nomenclature Committee of the International Union of Biochemistry (NC-IUB). Nomenclature of electron-transfer proteins. Recommendations 1989". The Journal of Biological Chemistry. 267 (1): 665–77. January 1992. doi:10.1016/S0021-9258(18)48544-4. PMID 1309757.
  2. ^ Allen JW, Ginger ML, Ferguson SJ (November 2004). "Maturation of the unusual single-cysteine (XXXCH) mitochondrial c-type cytochromes found in trypanosomatids must occur through a novel biogenesis pathway". The Biochemical Journal. 383 (Pt. 3): 537–42. doi:10.1042/BJ20040832. PMC 1133747. PMID 15500440.
  3. ^ Eaves DJ, Grove J, Staudenmann W, James P, Poole RK, White SA, Griffiths I, Cole JA (April 1998). "Involvement of products of the nrfEFG genes in the covalent attachment of haem c to a novel cysteine-lysine motif in the cytochrome c552 nitrite reductase from Escherichia coli". Molecular Microbiology. 28 (1): 205–16. doi:10.1046/j.1365-2958.1998.00792.x. PMID 9593308. S2CID 23841928.
  4. ^ Rodrigues ML, Oliveira TF, Pereira IA, Archer M (December 2006). "X-ray structure of the membrane-bound cytochrome c quinol dehydrogenase NrfH reveals novel haem coordination". The EMBO Journal. 25 (24): 5951–60. doi:10.1038/sj.emboj.7601439. PMC 1698886. PMID 17139260.
  5. ^ Hartshorne RS, Kern M, Meyer B, Clarke TA, Karas M, Richardson DJ, Simon J (May 2007). "A dedicated haem lyase is required for the maturation of a novel bacterial cytochrome c with unconventional covalent haem binding" (PDF). Molecular Microbiology. 64 (4): 1049–60. doi:10.1111/j.1365-2958.2007.05712.x. PMID 17501927. S2CID 20332910.
  6. ^ Assfalg M, Bertini I, Dolfi A, Turano P, Mauk AG, Rosell FI, Gray HB (March 2003). "Structural model for an alkaline form of ferricytochrome C" (PDF). Journal of the American Chemical Society. 125 (10): 2913–22. doi:10.1021/ja027180s. PMID 12617658.
  7. ^ Pettigrew GW, Moore GR (1987). "The Function of Bacterial and Photosynthetic Cytochromes C". Cytochromes C. Springer Series in Molecular Biology. Berlin Heidelberg: Springer. pp. 113–229. doi:10.1007/978-3-642-72698-9_3. ISBN 978-3-642-72698-9.