Structure of an Ancient Respiratory System.
Cell
; 173(7): 1636-1649.e16, 2018 06 14.
Article
em En
| MEDLINE
| ID: mdl-29754813
ABSTRACT
Hydrogen gas-evolving membrane-bound hydrogenase (MBH) and quinone-reducing complex I are homologous respiratory complexes with a common ancestor, but a structural basis for their evolutionary relationship is lacking. Here, we report the cryo-EM structure of a 14-subunit MBH from the hyperthermophile Pyrococcus furiosus. MBH contains a membrane-anchored hydrogenase module that is highly similar structurally to the quinone-binding Q-module of complex I while its membrane-embedded ion-translocation module can be divided into a H+- and a Na+-translocating unit. The H+-translocating unit is rotated 180° in-membrane with respect to its counterpart in complex I, leading to distinctive architectures for the two respiratory systems despite their largely conserved proton-pumping mechanisms. The Na+-translocating unit, absent in complex I, resembles that found in the Mrp H+/Na+ antiporter and enables hydrogen gas evolution by MBH to establish a Na+ gradient for ATP synthesis near 100°C. MBH also provides insights into Mrp structure and evolution of MBH-based respiratory enzymes.
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Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Proteínas Arqueais
/
Pyrococcus furiosus
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Hidrogenase
Idioma:
En
Ano de publicação:
2018
Tipo de documento:
Article