Pause and rotation of F1-ATPase during catalysis
Abstract
F1-ATPase is a rotary motor enzyme in which a single ATP molecule drives a 120° rotation of the central γ subunit relative to the surrounding α3β3 ring. Here, we show that the rotation of F1-ATPase spontaneously lapses into long (≈30 s) pauses during steady-state catalysis. The effects of ADP-Mg and mutation on the pauses, as well as kinetic comparison with bulk-phase catalysis, strongly indicate that the paused enzyme corresponds to the inactive state of F1-ATPase previously known as the ADP-Mg inhibited form in which F1-ATPase fails to release ADP-Mg from catalytic sites. The pausing position of the γ subunit deviates from the ATP-waiting position and is most likely the recently found intermediate 90° position.
- Publication:
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Proceedings of the National Academy of Science
- Pub Date:
- November 2001
- DOI:
- 10.1073/pnas.241365698
- Bibcode:
- 2001PNAS...9813649H
- Keywords:
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- Biophysics