27 February 2006 3D-localization of the a-subunit in F0F1-ATP synthase by time resolved single-molecule FRET
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FoF1-ATP synthases catalyze the ATP formation from ADP and phosphate in the membranes of mitochondria, chloroplasts and bacteria. Internal rotation of subunits couples the chemical reaction at the F1 part to the proton translocation through the Fo part. In these enzymes, the membrane-embedded a-subunit is part of the non-rotating 'stator' subunits and provides the proton channel of the Fo motor. At present, the relative position of the a-subunit is not known. We examined the rotary movements of the ε-subunit with respect to the non-rotating a-subunit by time resolved singlemolecule fluorescence resonance energy transfer (FRET) using a novel pulsed laser diode. Rotation of the ε-subunit during ATP hydrolysis was divided into three major steps. The stopping positions of ε resulted in three distinct FRET efficiency levels and FRET donor lifetimes. From these FRET efficiencies the position of the FRET donor at the asubunit was calculated. Different populations of the three resting positions of ε, which were observed previously, enabled us to scrutinize the models for the position of the a-subunit in the Fo part.
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Monika G. Düser, Monika G. Düser, Nawid Zarrabi, Nawid Zarrabi, Yumin Bi, Yumin Bi, Boris Zimmermann, Boris Zimmermann, Stanley D. Dunn, Stanley D. Dunn, Michael Börsch, Michael Börsch, "3D-localization of the a-subunit in F0F1-ATP synthase by time resolved single-molecule FRET", Proc. SPIE 6092, Ultrasensitive and Single-Molecule Detection Technologies, 60920H (27 February 2006); doi: 10.1117/12.647988; https://doi.org/10.1117/12.647988

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