Monitoring transient elastic energy storage within the rotary motors of single FoF1-ATP synthase by DCO-ALEX FRET

Stefan Ernst; Monika G. Düser; Nawid Zarrabi; Michael Börsch

doi:10.1117/12.907086

9 February 2012 Monitoring transient elastic energy storage within the rotary motors of single F_oF₁-ATP synthase by DCO-ALEX FRET

Stefan Ernst, Monika G. Düser, Nawid Zarrabi, Michael Börsch

Author Affiliations +

Proceedings Volume 8226, Multiphoton Microscopy in the Biomedical Sciences XII; 82260I (2012) https://doi.org/10.1117/12.907086
Event: SPIE BiOS, 2012, San Francisco, California, United States

Abstract

The enzyme F_oF₁-ATP synthase provides the 'chemical energy currency' adenosine triphosphate (ATP) for living cells. Catalysis is driven by mechanochemical coupling of subunit rotation within the enzyme with conformational changes in the three ATP binding sites. Proton translocation through the membrane-bound F_o part of ATP synthase powers a 10-step rotary motion of the ring of c subunits. This rotation is transmitted to the γ and ε subunits of the F₁ part. Because γ and ε subunits rotate in 120° steps, we aim to unravel this symmetry mismatch by real time monitoring subunit rotation using single-molecule Förster resonance energy transfer (FRET). One fluorophore is attached specifically to the F₁ motor, another one to the F_o motor of the liposome-reconstituted enzyme. Photophysical artifacts due to spectral fluctuations of the single fluorophores are minimized by a previously developed duty cycle-optimized alternating laser excitation scheme (DCO-ALEX). We report the detection of reversible elastic deformations between the rotor parts of F_o and F₁ and estimate the maximum angular displacement during the load-free rotation using Monte Carlo simulations.

Citation Download Citation

Stefan Ernst, Monika G. Düser, Nawid Zarrabi, and Michael Börsch "Monitoring transient elastic energy storage within the rotary motors of single F_oF₁-ATP synthase by DCO-ALEX FRET", Proc. SPIE 8226, Multiphoton Microscopy in the Biomedical Sciences XII, 82260I (9 February 2012); https://doi.org/10.1117/12.907086

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