Details

Autor(en) / Beteiligte

• Letts, James A.
• Fiedorczuk, Karol
• Sazanov, Leonid A.

Titel

The architecture of respiratory supercomplexes

Ist Teil von

• Nature (London), 2016-09, Vol.537 (7622), p.644-648

Ort / Verlag

London: Nature Publishing Group UK

Erscheinungsjahr

2016

Quelle

MEDLINE

Beschreibungen/Notizen

• Mitochondrial electron transport chain complexes are organized into supercomplexes responsible for carrying out cellular respiration. Here we present three architectures of mammalian (ovine) supercomplexes determined by cryo-electron microscopy. We identify two distinct arrangements of supercomplex CICIII 2 CIV (the respirasome)—a major ‘tight’ form and a minor ‘loose’ form (resolved at the resolution of 5.8 Å and 6.7 Å, respectively), which may represent different stages in supercomplex assembly or disassembly. We have also determined an architecture of supercomplex CICIII 2 at 7.8 Å resolution. All observed density can be attributed to the known 80 subunits of the individual complexes, including 132 transmembrane helices. The individual complexes form tight interactions that vary between the architectures, with complex IV subunit COX7a switching contact from complex III to complex I. The arrangement of active sites within the supercomplex may help control reactive oxygen species production. To our knowledge, these are the first complete architectures of the dominant, physiologically relevant state of the electron transport chain. Respirasomes are supercomplexes of mitochondrial electron transport chain complexes that are responsible for cellular respiration and energy production; cryo-electron microscopy structures of mammalian (sheep) respirasomes are presented. Inside the mammalian respirasome supercomplex Mitochondrial electron transport chain complexes are responsible for cellular respiration and energy production. They are organized in supercomplexes called respirasomes. Two studies in this issue of Nature report cryo-electron microscopy structures of the supercomplex consisting of complex I, the dimer of complex III and complex IV at resolutions ranging from 5.4 Å to 7.8 Å. Maojun Yang and colleagues study the respirasome isolated from porcine heart, whereas Leonid Sazanov and colleagues obtain it from ovine heart. The structures provide insights into the organization of subunits within complexes and the interactions between the complexes.