6SH3

Structure of the ADP state of the heptameric Bcs1 AAA-ATPase

Summary for 6SH3

• Entry DOI: 10.2210/pdb6sh3/pdb
• EMDB information: 10192
• Descriptor: Mitochondrial chaperone BCS1, ADENOSINE-5'-DIPHOSPHATE (2 entities in total)
• Functional Keywords: translocation, rieske, mitochondira, inner mitochondiral membrane, translocase
• Biological source: Saccharomyces cerevisiae (Baker's yeast)
• Total number of polymer chains: 7
• Total formula weight: 361196.76

Authors

Kater, L.,Beckmann, R. (deposition date: 2019-08-05, release date: 2020-02-05, Last modification date: 2024-05-22)

Primary citation

Kater, L.,Wagener, N.,Berninghausen, O.,Becker, T.,Neupert, W.,Beckmann, R.
Structure of the Bcs1 AAA-ATPase suggests an airlock-like translocation mechanism for folded proteins.
Nat.Struct.Mol.Biol., 27:142-149, 2020

PubMed Abstract: Some proteins require completion of folding before translocation across a membrane into another cellular compartment. Yet the permeability barrier of the membrane should not be compromised and mechanisms have remained mostly elusive. Here, we present the structure of Saccharomyces cerevisiae Bcs1, an AAA-ATPase of the inner mitochondrial membrane. Bcs1 facilitates the translocation of the Rieske protein, Rip1, which requires folding and incorporation of a 2Fe-2S cluster before translocation and subsequent integration into the bc1 complex. Surprisingly, Bcs1 assembles into exclusively heptameric homo-oligomers, with each protomer consisting of an amphipathic transmembrane helix, a middle domain and an ATPase domain. Together they form two aqueous vestibules, the first being accessible from the mitochondrial matrix and the second positioned in the inner membrane, with both separated by the seal-forming middle domain. On the basis of this unique architecture, we propose an airlock-like translocation mechanism for folded Rip1.

PubMed: 31988523
DOI: 10.1038/s41594-019-0364-1

Experimental method

ELECTRON MICROSCOPY (3.4 Å)