6ZKO

Native complex I, closed

Summary for 6ZKO

• Entry DOI: 10.2210/pdb6zko/pdb
• EMDB information: 11256
• Descriptor: NADH dehydrogenase [ubiquinone] flavoprotein 1, mitochondrial, NADH-ubiquinone oxidoreductase chain 6, NADH-ubiquinone oxidoreductase chain 4L, ... (56 entities in total)
• Functional Keywords: complex, respiration, nadh, proton pump, mitochondria, iron-sulphur cluster, oxidoreductase, membrane protein, electron transport
• Biological source: Ovis aries (Sheep); More
• Total number of polymer chains: 45
• Total formula weight: 1079504.79

Authors

Kampjut, D.,Sazanov, L.A. (deposition date: 2020-06-30, release date: 2020-10-07, Last modification date: 2020-11-11)

Primary citation

Kampjut, D.,Sazanov, L.A.
The coupling mechanism of mammalian respiratory complex I.
Science, 370:-, 2020

PubMed Abstract: Mitochondrial complex I couples NADH:ubiquinone oxidoreduction to proton pumping by an unknown mechanism. Here, we present cryo-electron microscopy structures of ovine complex I in five different conditions, including turnover, at resolutions up to 2.3 to 2.5 angstroms. Resolved water molecules allowed us to experimentally define the proton translocation pathways. Quinone binds at three positions along the quinone cavity, as does the inhibitor rotenone that also binds within subunit ND4. Dramatic conformational changes around the quinone cavity couple the redox reaction to proton translocation during open-to-closed state transitions of the enzyme. In the induced deactive state, the open conformation is arrested by the ND6 subunit. We propose a detailed molecular coupling mechanism of complex I, which is an unexpected combination of conformational changes and electrostatic interactions.

PubMed: 32972993
DOI: 10.1126/science.abc4209

Experimental method

ELECTRON MICROSCOPY (3.8 Å)