8TBY

Apo Bcs1, unsymmetrized

Summary for 8TBY

• Entry DOI: 10.2210/pdb8tby/pdb
• EMDB information: 41148
• Descriptor: Mitochondrial chaperone BCS1 (1 entity in total)
• Functional Keywords: heptamer, aaa-atpase, translocase
• Biological source: Mus musculus (house mouse)
• Total number of polymer chains: 7
• Total formula weight: 338029.21

Authors

Zhan, J.,Xia, D. (deposition date: 2023-06-29, release date: 2024-06-05, Last modification date: 2024-06-12)

Primary citation

Zhan, J.,Zeher, A.,Huang, R.,Tang, W.K.,Jenkins, L.M.,Xia, D.
Conformations of Bcs1L undergoing ATP hydrolysis suggest a concerted translocation mechanism for folded iron-sulfur protein substrate.
Nat Commun, 15:4655-4655, 2024

PubMed Abstract: 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.

PubMed: 38821922
DOI: 10.1038/s41467-024-49029-y

Experimental method

ELECTRON MICROSCOPY (4.4 Å)