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Structural basis for the interaction of the chaperone Cbp3 with newly synthesized cytochrome b during mitochondrial respiratory chain assembly
Authors:
Mama
Ndi
(Stockholm University)
,
Geoffrey
Masuyer
(Stockholm University)
,
Hannah
Dawitz
(Stockholm University)
,
Andreas
Carlström
(Stockholm University)
,
Mirco
Michel
(Stockholm University)
,
Arne
Elofsson
(Stockholm University)
,
Mikaela
Rapp
(Stockholm University)
,
Pal
Stenmark
(Stockholm University)
,
Martin
Ott
(Stockholm University)
Co-authored by industrial partner:
No
Type:
Journal Paper
Journal:
Journal Of Biological Chemistry
State:
Published (Approved)
Published:
September 2019
Diamond Proposal Number(s):
11265

Abstract: 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.
Journal Keywords: complex III; assembly factor; mMitochondrial translation; ubiquinol-cytochrome c chaperone domain; electron transfer chain; structural biology; protein assembly; mitochondria; membrane biogenesis; protein cross-linking; respiratory chain
Subject Areas:
Biology and Bio-materials,
Chemistry
Instruments:
I04-1-Macromolecular Crystallography (fixed wavelength)
Added On:
25/09/2019 12:01
Discipline Tags:
Biochemistry
Chemistry
Structural biology
Life Sciences & Biotech
Technical Tags:
Diffraction
Macromolecular Crystallography (MX)