Tracing the tail of ubiquinone in mitochondrial complex I.

摘要: Mitochondrial complex I (proton pumping NADH:ubiquinone oxidoreductase) is the largest and most complicated component of respiratory electron transfer chain. Despite its central role in biological energy conversion structure function this membrane integral multiprotein still poorly understood. Recent insights into by X-ray crystallography have shown that iron-sulfur cluster N2, immediate donor for ubiquinone, resides about 30A above domain mutagenesis studies suggested active site hydrophobic substrate located next to redox-center. To trace path tail ubiquinone when it enters peripheral arm I, we performed an extensive structure/function analysis from Yarrowia lipolytica monitoring interaction site-directed mutants with five derivatives carrying different tails. The catalytic activity a subset was strictly dependent on presence intact isoprenoid moieties tail. Overall consistent picture emerged suggesting through narrow at interface between 49-kDa PSST subunits. Most notably identified set methionines seems form gate reminiscent M-domains involved targeting sequences signal recognition particle endoplasmic reticulum. Interestingly, two amino acids critical are bovine could show one these exchanges responsible lower sensitivity Y. towards inhibitor rotenone. This article part Special Issue entitled: 17th European Bioenergetics Conference (EBEC 2012).