6H8K

Crystal structure of a variant (Q133C in PSST) of Yarrowia lipolytica complex I

This is a non-PDB format compatible entry.

Summary for 6H8K

• Entry DOI: 10.2210/pdb6h8k/pdb
• Descriptor: NADH-ubiquinone oxidoreductase chain 1, NUEM protein, NUGM protein, ... (50 entities in total)
• Functional Keywords: membrane protein, respiratory chain, mitochondrial, nadh:ubiquinone oxidoreductase, oxidoreductase
• Biological source: Yarrowia lipolytica (Candida lipolytica); More
• Total number of polymer chains: 73
• Total formula weight: 580527.83

Authors

Wirth, C.,Galemou Yoga, E.,Zickermann, V.,Hunte, C. (deposition date: 2018-08-02, release date: 2018-12-26, Last modification date: 2024-11-20)

Primary citation

Cabrera-Orefice, A.,Yoga, E.G.,Wirth, C.,Siegmund, K.,Zwicker, K.,Guerrero-Castillo, S.,Zickermann, V.,Hunte, C.,Brandt, U.
Locking loop movement in the ubiquinone pocket of complex I disengages the proton pumps.
Nat Commun, 9:4500-4500, 2018

PubMed Abstract: Complex I (proton-pumping NADH:ubiquinone oxidoreductase) is the largest enzyme of the mitochondrial respiratory chain and a significant source of reactive oxygen species (ROS). We hypothesized that during energy conversion by complex I, electron transfer onto ubiquinone triggers the concerted rearrangement of three protein loops of subunits ND1, ND3, and 49-kDa thereby generating the power-stoke driving proton pumping. Here we show that fixing loop TMH1-2 to the nearby subunit PSST via a disulfide bridge introduced by site-directed mutagenesis reversibly disengages proton pumping without impairing ubiquinone reduction, inhibitor binding or the Active/Deactive transition. The X-ray structure of mutant complex I indicates that the disulfide bridge immobilizes but does not displace the tip of loop TMH1-2. We conclude that movement of loop TMH1-2 located at the ubiquinone-binding pocket is required to drive proton pumping corroborating one of the central predictions of our model for the mechanism of energy conversion by complex I proposed earlier.

PubMed: 30374105
DOI: 10.1038/s41467-018-06955-y

Experimental method

X-RAY DIFFRACTION (3.79 Å)