3RKO

Crystal structure of the membrane domain of respiratory complex I from E. coli at 3.0 angstrom resolution

Summary for 3RKO

• Entry DOI: 10.2210/pdb3rko/pdb
• Descriptor: NADH-QUINONE OXIDOREDUCTASE SUBUNIT L, NADH-QUINONE OXIDOREDUCTASE SUBUNIT M, NADH-QUINONE OXIDOREDUCTASE SUBUNIT N, ... (9 entities in total)
• Functional Keywords: complex i, oxidoreductase, proton pump, membrane protein, nadh, ubiquinone, cytoplasmic membrane
• Biological source: Escherichia coli; More
• Cellular location: Membrane; Multi-pass membrane protein (By similarity): C6E9S4 C6E9S5 C6E9R4; Cell inner membrane; Multi-pass membrane protein (By similarity). Membrane; Multi-pass membrane protein (By similarity): C6E9S6
• Total number of polymer chains: 12
• Total formula weight: 450857.48

Authors

Efremov, R.G.,Sazanov, L.A. (deposition date: 2011-04-18, release date: 2011-08-03, Last modification date: 2024-02-28)

Primary citation

Efremov, R.G.,Sazanov, L.A.
Structure of the membrane domain of respiratory complex I.
Nature, 476:414-420, 2011

PubMed Abstract: Complex I is the first and largest enzyme of the respiratory chain, coupling electron transfer between NADH and ubiquinone to the translocation of four protons across the membrane. It has a central role in cellular energy production and has been implicated in many human neurodegenerative diseases. The L-shaped enzyme consists of hydrophilic and membrane domains. Previously, we determined the structure of the hydrophilic domain. Here we report the crystal structure of the Esherichia coli complex I membrane domain at 3.0 Å resolution. It includes six subunits, NuoL, NuoM, NuoN, NuoA, NuoJ and NuoK, with 55 transmembrane helices. The fold of the homologous antiporter-like subunits L, M and N is novel, with two inverted structural repeats of five transmembrane helices arranged, unusually, face-to-back. Each repeat includes a discontinuous transmembrane helix and forms half of a channel across the membrane. A network of conserved polar residues connects the two half-channels, completing the proton translocation pathway. Unexpectedly, lysines rather than carboxylate residues act as the main elements of the proton pump in these subunits. The fourth probable proton-translocation channel is at the interface of subunits N, K, J and A. The structure indicates that proton translocation in complex I, uniquely, involves coordinated conformational changes in six symmetrical structural elements.

PubMed: 21822288
DOI: 10.1038/nature10330

Experimental method

X-RAY DIFFRACTION (3 Å)