Abstract

The yeast cytochrome bc1 complex, a component of the mitochondrial respiratory chain, is composed of ten distinct protein subunits. In the assembly of the bc1 complex, some ancillary proteins, such as the chaperone Bcs1p, are actively involved. The deletion of the nuclear gene encoding this chaperone caused the arrest of the bc1 assembly and the formation of a functionally inactive bc1 core structure of about 500-kDa. This immature bc1 core structure could represent, on the one hand, a true assembly intermediate or, on the other hand, a degradation product and/or an incorrect product of assembly. The experiments here reported show that the gradual expression of Bcs1p in the yeast strain lacking this protein was progressively able to rescue the bc1 core structure leading to the formation of the functional homodimeric bc1 complex. Following Bcs1p expression, the mature bc1 complex was also progressively converted into two supercomplexes with the cytochrome c oxidase complex. The capability of restoring the bc1 complex and the supercomplexes was also possessed by the mutated yeast R81C Bcsp1. Notably, in the human ortholog BCS1L, the corresponding point mutation (R45C) was instead the cause of a severe bc1 complex deficiency. Differently from the yeast R81C Bcs1p, two other mutated Bcs1p's (K192P and F401I) were unable to recover the bc1 core structure in yeast. This study identifies for the first time a productive assembly intermediate of the yeast bc1 complex and gives new insights into the molecular mechanisms involved in the last steps of bc1 assembly.

Autore Pugliese

• Zara Vincenzo

Tutti gli autori

• Conte L. , Trumpower B.L. , Zara V.

Titolo volume/Rivista

BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH

Anno di pubblicazione

2011

ISSN

0167-4889

ISBN

Non Disponibile

Numero di citazioni Wos

9

Ultimo Aggiornamento Citazioni

25/04/2018

Numero di citazioni Scopus

12

Ultimo Aggiornamento Citazioni

24/04/2018

Settori ERC

Non Disponibile

Codici ASJC

Non Disponibile