3M9C

Crystal structure of the membrane domain of respiratory complex I from Escherichia coli

Summary for 3M9C

• Entry DOI: 10.2210/pdb3m9c/pdb
• Related: 3M9S
• Descriptor: NADH-quinone oxidoreductase subunit NuoL, NADH-quinone oxidoreductase subunit NuoM, NADH-quinone oxidoreductase subunit NuoN, ... (4 entities in total)
• Functional Keywords: membrane protein, complex i, oxidoreductase, electron transport, respiratory chain
• Biological source: Escherichia coli; More
• Total number of polymer chains: 4
• Total formula weight: 129771.64

Authors

Efremov, R.G.,Baradaran, R.,Sazanov, L.A. (deposition date: 2010-03-22, release date: 2010-05-26, Last modification date: 2024-02-21)

Primary citation

Efremov, R.G.,Baradaran, R.,Sazanov, L.A.
The architecture of respiratory complex I
Nature, 465:441-445, 2010

PubMed Abstract: Complex I is the first enzyme of the respiratory chain and has a central role in cellular energy production, coupling electron transfer between NADH and quinone to proton translocation by an unknown mechanism. Dysfunction of complex I has been implicated in many human neurodegenerative diseases. We have determined the structure of its hydrophilic domain previously. Here, we report the alpha-helical structure of the membrane domain of complex I from Escherichia coli at 3.9 A resolution. The antiporter-like subunits NuoL/M/N each contain 14 conserved transmembrane (TM) helices. Two of them are discontinuous, as in some transporters. Unexpectedly, subunit NuoL also contains a 110-A long amphipathic alpha-helix, spanning almost the entire length of the domain. Furthermore, we have determined the structure of the entire complex I from Thermus thermophilus at 4.5 A resolution. The L-shaped assembly consists of the alpha-helical model for the membrane domain, with 63 TM helices, and the known structure of the hydrophilic domain. The architecture of the complex provides strong clues about the coupling mechanism: the conformational changes at the interface of the two main domains may drive the long amphipathic alpha-helix of NuoL in a piston-like motion, tilting nearby discontinuous TM helices, resulting in proton translocation.

PubMed: 20505720
DOI: 10.1038/nature09066

Experimental method

X-RAY DIFFRACTION (3.9 Å)