Dresden 2003 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe
CPP: Chemische Physik und Polymerphysik
CPP 22: POSTER C
CPP 22.5: Poster
Donnerstag, 27. März 2003, 12:00–14:00, ZEU/250
Stepwise rotation of the gamma-subunit of EFoF1-ATP synthase — •Nawid Zarrabi1, Boris Zimmermann2, Manuel Dietz2, Peter Grber2, Jrg Wrachtrup1, and Michael Brsch1 — 13. Physikalisches Institut, Pfaffenwaldring 57, 70569 Stuttgart — 2Institut fr Physikalische Chemie, Albertstr. 23a, 79104 Freiburg
H+-ATP synthases catalyze the synthesis of ATP by coupling two rotary motors. To monitor inter-subunit rotation during ATP hydrolysis, we attached two fluorophores - Cy5 at the rotating gamma-subunit and rhodamine B at one beta-subunit - and reconstituted the enzymes fully functional into liposomes. The proteoliposomes were immobilized on the glass surface of cover slides via biotin/streptavidin-technology. Fluorescence resonance energy transfer (FRET) was monitored in photon bursts with a scanning confocal setup for single-molecule detection. Incubation with AMPPNP resulted in stable intensity ratios within a burst and three different FRET efficiencies. With ATP a consecutive order of three distinguishable FRET efficiencies was observed indicating a stepwise movement of the gamma-subunit [1]. Detecting gamma-subunit rotation during hydrolysis of ATP-gamma-S, which is hydrolysed by a factor of 30 slower than ATP, we could detect additional substeps comparable to those in the isolated F1 parts [2]. References: [1] M. Börsch, M. Diez, B. Zimmermann, R. Reuter, P. Gräber (2002) FEBS lett. 527, 147-152. [2] R. Yasuda, H. Noji, M. Yoshida, K. Kinosita Jr., H. Itoh (2001) nature 410, 898-904.