Détail de la notice
Titre du Document
Maturation of the unusual single-cysteine (XXXCH) mitochondrial c-type cytochromes found in trypanosomatids must occur through a novel biogenesis pathway
Auteur(s)
ALLEN James W. A. ; GINGER Michael L. ; FERGUSON Stuart J.
Résumé
The c-type cytochromes are characterized by the covalent attachment of haem to the polypeptide via thioether bonds formed from haem vinyl groups and, normally, the thiols of two cysteines in a CXXCH motif. Intriguingly, the mitochondrial cytochromes c and c1from two euglenids and the Trypanosomatidae contain only a single cysteine within the haem-binding motif (XXXCH). There are three known distinct pathways by which c-type cytochromes are matured post-translationally in different organisms. The absence of genes encoding any of these c-type cytochrome biogenesis machineries is established here by analysis of six trypanosomatid genomes, and correlates with the presence of single-cysteine cytochromes c and c1. In contrast, we have identified a comprehensive catalogue of proteins required for a typical mitochondrial oxidative phosphorylation apparatus. Neither spontaneous norcatalysed maturation of the single-cysteine Trypanosoma brucei cytochrome c occurred in Escherichia coli. However, a CXXCH variant was matured by the E. coli cytochrome c maturation machinery, confirming the proposed requirement of the latter for two cysteines in the haem-binding motif and indicating that T. brucei cytochrome c can accommodate a second cysteine in a CXXCH motif. The single-cysteine haem attachment conserved in cytochromes c and c, of the trypanosomatids is suggested to be related to their cytochrome c maturation machinery, and the environment in the mitochondrial intermembrane sp
Editeur
Portland Press
Identifiant
ISSN : 0264-6021
Source
Biochemical journal (London. 1984) A. 2004, vol. 383, 3, pp. 537-542 [6 pages]
Langue
Anglais
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