6XKV image
Entry Detail
PDB ID:
6XKV
EMDB ID:
Title:
R. capsulatus cyt bc1 with both FeS proteins in b position (CIII2 b-b)
Biological Source:
PDB Version:
Deposition Date:
2020-06-27
Release Date:
2020-12-30
Method Details:
Experimental Method:
Resolution:
3.50 Å
Aggregation State:
PARTICLE
Reconstruction Method:
SINGLE PARTICLE
Macromolecular Entities
Polymer Type:polypeptide(L)
Description:Cytochrome b
Chain IDs:A (auth: C), C (auth: P)
Chain Length:437
Number of Molecules:2
Biological Source:Rhodobacter capsulatus (strain ATCC BAA-309 / NBRC 16581 / SB1003)
Polymer Type:polypeptide(L)
Description:Cytochrome c1
Chain IDs:B (auth: D), D (auth: Q)
Chain Length:279
Number of Molecules:2
Biological Source:Rhodobacter capsulatus (strain ATCC BAA-309 / NBRC 16581 / SB1003)
Polymer Type:polypeptide(L)
Description:Ubiquinol-cytochrome c reductase iron-sulfur subunit
Chain IDs:E, F (auth: R)
Chain Length:191
Number of Molecules:2
Biological Source:Rhodobacter capsulatus (strain ATCC BAA-309 / NBRC 16581 / SB1003)
Primary Citation
Cryo-EM structures of engineered active bc 1 -cbb 3 type CIII 2 CIV super-complexes and electronic communication between the complexes.
Nat Commun 12 929 929 (2021)
PMID: 33568648 DOI: 10.1038/s41467-021-21051-4

Abstact

Respiratory electron transport complexes are organized as individual entities or combined as large supercomplexes (SC). Gram-negative bacteria deploy a mitochondrial-like cytochrome (cyt) bc1 (Complex III, CIII2), and may have specific cbb3-type cyt c oxidases (Complex IV, CIV) instead of the canonical aa3-type CIV. Electron transfer between these complexes is mediated by soluble (c2) and membrane-anchored (cy) cyts. Here, we report the structure of an engineered bc1-cbb3 type SC (CIII2CIV, 5.2 Å resolution) and three conformers of native CIII2 (3.3 Å resolution). The SC is active in vivo and in vitro, contains all catalytic subunits and cofactors, and two extra transmembrane helices attributed to cyt cy and the assembly factor CcoH. The cyt cy is integral to SC, its cyt domain is mobile and it conveys electrons to CIV differently than cyt c2. The successful production of a native-like functional SC and determination of its structure illustrate the characteristics of membrane-confined and membrane-external respiratory electron transport pathways in Gram-negative bacteria.

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