bims-cytox1 Biomed News
on Cytochrome oxidase subunit 1
Issue of 2019‒09‒22
two papers selected by
Gavin McStay
Staffordshire University

  1. J Biol Chem. 2019 Sep 19. pii: jbc.RA119.010483. [Epub ahead of print]
    Ndi M, Masuyer G, Dawitz H, Carlström A, Michel M, Elofsson A, Rapp M, Stenmark P, Ott M.
      Assembly of the mitochondrial respiratory chain requires the coordinated synthesis of mitochondrial and nuclear encoded subunits, redox co-factor acquisition, and correct joining of the subunits to form functional complexes. The conserved Cbp3-Cbp6 chaperone complex binds newly synthesized cytochrome b and supports the ordered acquisition of the heme co-factors. Moreover, it functions as a translational activator by interacting with the mitoribosome. Cbp3 consists of two distinct domains, an N-terminal domain present in mitochondrial Cbp3 homologs, and a highly conserved C-terminal domain comprising a ubiquinol-cytochrome c chaperone region. Here, we solved the crystal structure of this C-terminal domain from a bacterial homolog at 1.4 Å resolution, revealing a unique all-helical fold. This structure allowed mapping of the interaction sites of yeast Cbp3 with Cbp6 and cytochrome b via site-specific photo-crosslinking. We propose that mitochondrial Cbp3 homologs carry an N-terminal extension that positions the conserved C-terminal domain at the ribosomal tunnel exit for an efficient interaction with its substrate, the newly synthesized cytochrome b protein.
    Keywords:  assembly factor; complex III; electron transfer chain; mMitochondrial translation; membrane biogenesis; mitochondria; protein assembly; protein cross-linking; respiratory chain; structural biology; ubiquinol-cytochrome c chaperone domain
  2. Mol Genet Metab Rep. 2019 Dec;21 100519
    Finsterer J.
    Keywords:  Headache; Lactic acidosis; Mitochondrial; Myopathy; Oxidative phosphorylation; mtDNA