Cryo-EM structures of engineered active bc1-cbb3 type CIII2CIV super-complexes and electronic communication between the complexes.
Nat Commun
; 12(1): 929, 2021 02 10.
Article
em En
| MEDLINE
| ID: mdl-33568648
ABSTRACT
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.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Proteínas de Bactérias
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Rhodobacter capsulatus
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Complexo IV da Cadeia de Transporte de Elétrons
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Complexo III da Cadeia de Transporte de Elétrons
Idioma:
En
Ano de publicação:
2021
Tipo de documento:
Article