Investigation of the Molecular Mechanisms of the Eukaryotic Cytochrome-c Maturation System

Autor: Ana V. Silva, Maria O. Firmino, Nazua L. Costa, Ricardo O. Louro, Catarina M. Paquete
Jazyk: angličtina
Rok vydání: 2022
Předmět:
Zdroj: Biomolecules, Vol 12, Iss 4, p 549 (2022)
Druh dokumentu: article
ISSN: 2218-273X
DOI: 10.3390/biom12040549
Popis: Cytochromes-c are ubiquitous heme proteins with enormous impact at the cellular level, being key players in metabolic processes such as electron transfer chains and apoptosis. The assembly of these proteins requires maturation systems that catalyse the formation of the covalent thioether bond between two cysteine residues and the vinyl groups of the heme. System III is the maturation system present in Eukaryotes, designated CcHL or HCCS. This System requires a specific amino acid sequence in the apocytochrome to be recognized as a substrate and for heme insertion. To explore the recognition mechanisms of CcHL, the bacterial tetraheme cytochrome STC from Shewanella oneidensis MR-1, which is not a native substrate for System III, was mutated to be identified as a substrate. The results obtained show that it is possible to convert a bacterial cytochrome as a substrate by CcHL, but the presence of the recognition sequence is not the only factor that induces the maturation of a holocytochrome by System III. The location of this sequence in the polypeptide also plays a role in the maturation of the c-type cytochrome. Furthermore, CcHL appears to be able to catalyse the binding of only one heme per polypeptide chain, being unable to assemble multiheme cytochromes c, in contrast with bacterial maturation systems.
Databáze: Directory of Open Access Journals
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