A Novel, Enzymatically Active Conformation of theEscherichia coli NADH:Ubiquinone Oxidoreductase (Complex I)

Electron microscopy has demonstrated the unusual L-shaped structure of the respiratory complex I consisting of two arms, which are arranged perpendicular to each other. We found that the Escherichia coli complex I has an additional stable conformation, with the two arms arranged side by side, result...

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Bibliographic Details
Published in:The Journal of biological chemistry 2002-05, Vol.277 (20), p.17970
Main Authors: Bettina Böttcher, Dierk Scheide, Micaela Hesterberg, Luitgard Nagel-Steger, Thorsten Friedrich
Format: Article
Language:English
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Summary:Electron microscopy has demonstrated the unusual L-shaped structure of the respiratory complex I consisting of two arms, which are arranged perpendicular to each other. We found that the Escherichia coli complex I has an additional stable conformation, with the two arms arranged side by side, resulting in a horseshoe-shaped structure. The structure of both conformations was determined by means of electron microscopy of gold thioglucose-stained single particles. They were distinguished from each other by titration of the complex with polyethylene glycol and by means of analytical ultracentrifugation. The transition between the two conformations is induced by the ionic strength of the buffer and is reversible. Only the horseshoe-shaped complex I exhibits enzyme activity in detergent solution, which is abolished by the addition of salt. Therefore, it is proposed that this structure is the native conformation of the complex in the membrane.
ISSN:0021-9258
1083-351X
DOI:10.1074/jbc.M112357200