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Structural basis for the interaction of the chaperone Cbp3 with newly synthesized cytochrome b during mitochondrial respiratory chain assembly

Ndi, Mama ; Masuyer, Geoffrey ; Dawitz, Hannah ; Carlström, Andreas ; Michel, Mirco ; Elofsson, Arne ; Rapp, Mikaela ; Stenmark, Pål LU and Ott, Martin (2019) In Journal of Biological Chemistry
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... (More)

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.

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author
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publication status
epub
in
Journal of Biological Chemistry
publisher
ASBMB
external identifiers
  • scopus:85074705948
  • pmid:31537648
ISSN
1083-351X
DOI
10.1074/jbc.RA119.010483
language
English
LU publication?
no
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Published under license by The American Society for Biochemistry and Molecular Biology, Inc.
id
983873f2-a61a-4057-9d92-23182a2bab22
date added to LUP
2019-09-25 14:24:15
date last changed
2020-01-13 02:25:11
@article{983873f2-a61a-4057-9d92-23182a2bab22,
  abstract     = {<p>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.</p>},
  author       = {Ndi, Mama and Masuyer, Geoffrey and Dawitz, Hannah and Carlström, Andreas and Michel, Mirco and Elofsson, Arne and Rapp, Mikaela and Stenmark, Pål and Ott, Martin},
  issn         = {1083-351X},
  language     = {eng},
  month        = {09},
  publisher    = {ASBMB},
  series       = {Journal of Biological Chemistry},
  title        = {Structural basis for the interaction of the chaperone Cbp3 with newly synthesized cytochrome b during mitochondrial respiratory chain assembly},
  url          = {http://dx.doi.org/10.1074/jbc.RA119.010483},
  doi          = {10.1074/jbc.RA119.010483},
  year         = {2019},
}