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Investigation of the Molecular Mechanisms of the Eukaryotic Cytochrome-c Maturation System
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Orientador(es)
Resumo(s)
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.
Descrição
Funding Information: Financial support was provided by European EC Horizon 2020 TIMB3 (Project 810856). Financial support was also provided by Project MOSTMICRO-ITQB with refs UIDB/04612/2020 and UIDP/04612/2020. Fundação para a Ciência e a Tecnologia (FCT) Portugal is also acknowledged for funding through project PTDC/BIA-BQM/30176/2017, and through SFRH/BD/129067/2017 to A.V.S. Funding Information: Funding: Financial support was provided by European EC Horizon2020 TIMB3 (Project 810856). Financial support was also provided by Project MOSTMICRO-ITQB with refs UIDB/04612/2020 and UIDP/04612/2020. Fundação para a Ciência e a Tecnologia (FCT) Portugal is also acknowledged for funding through project PTDC/BIA-BQM/30176/2017, and through SFRH/BD/129067/2017 to A.V.S. Publisher Copyright: © 2022 by the authors. Licensee MDPI, Basel, Switzerland.
Palavras-chave
CcHL lyase multiheme cytochrome Small Tetraheme Cytochrome Biochemistry Molecular Biology