MPS seminar Ulrich Brandt

Structural and Functional Insights into Mitochondrial Complex I

The molecular mechanism how complex I (NADH:ubiquinone oxidoreductase) links electron transfer to proton translocation is still elusive. The ubiquinone reducing catalytic core of complex I resides at the interface between the 49-kDa and the PSST subunit of the peripheral arm where iron-sulfur cluster N2 serves as the immediate reductant of ubiquinone. In an extensive mutagenesis study based on the recently published partial structure of bacterial complex I, we have identified the entry pathway for ubiquinone and domains interacting with hydrophobic complex I. Single particle analysis of antibody decorated complex I indicated that the 49-kDa subunit is located surprisingly far away from the membrane arm. This unexpected result was confirmed by further structural studies with a subcomplex of complex I lacking the 51-kDa and 24-kDa subunits. Electron microscopic 3D reconstructions of this subcomplex allowed positioning the partial structure of the bacterial complex within Y. lipolytica complex I.

 

Dec 12 2008, 10:15 sal A.

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