8T7U image
Entry Detail
PDB ID:
8T7U
EMDB ID:
Keywords:
Title:
ADP-bound Bcs1 (unsymmetrized)
Biological Source:
Source Organism:
Host Organism:
PDB Version:
Deposition Date:
2023-06-21
Release Date:
2024-06-05
Method Details:
Experimental Method:
Resolution:
3.74 Å
Aggregation State:
PARTICLE
Reconstruction Method:
SINGLE PARTICLE
Macromolecular Entities
Polymer Type:polypeptide(L)
Description:Mitochondrial chaperone BCS1
Chain IDs:A, B (auth: G), C (auth: B), D (auth: C), E (auth: D), F (auth: E), G (auth: F)
Chain Length:424
Number of Molecules:7
Biological Source:Mus musculus
Ligand Molecules
Primary Citation
Conformations of Bcs1L undergoing ATP hydrolysis suggest a concerted translocation mechanism for folded iron-sulfur protein substrate.
Nat Commun 15 4655 4655 (2024)
PMID: 38821922 DOI: 10.1038/s41467-024-49029-y

Abstact

The human AAA-ATPase Bcs1L translocates the fully assembled Rieske iron-sulfur protein (ISP) precursor across the mitochondrial inner membrane, enabling respiratory Complex III assembly. Exactly how the folded substrate is bound to and released from Bcs1L has been unclear, and there has been ongoing debate as to whether subunits of Bcs1L act in sequence or in unison hydrolyzing ATP when moving the protein cargo. Here, we captured Bcs1L conformations by cryo-EM during active ATP hydrolysis in the presence or absence of ISP substrate. In contrast to the threading mechanism widely employed by AAA proteins in substrate translocation, subunits of Bcs1L alternate uniformly between ATP and ADP conformations without detectable intermediates that have different, co-existing nucleotide states, indicating that the subunits act in concert. We further show that the ISP can be trapped by Bcs1 when its subunits are all in the ADP-bound state, which we propose to be released in the apo form.

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Primary Citation of related structures