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Updated: Aug 29, 2026

Dissecting Mechanoenzymatic Properties of Processive Myosins with Ultrafast Force-Clamp Spectroscopy
Published on: July 1, 2021
Chemomechanical coupling in F1-ATPase revealed by simultaneous observation of nucleotide kinetics and rotation
Takayuki Nishizaka1, Kazuhiro Oiwa, Hiroyuki Noji
1Kansai Advanced Research Center, Protein Biophysics Group, Iwaoka 588-2, Nishi-ku, Kobe 651-2492, Japan. takayuki.nishizaka@gakushuin.ac.jp
Abstract:
F(1)-ATPase is a rotary molecular motor in which unidirectional rotation of the central gamma subunit is powered by ATP hydrolysis in three catalytic sites arranged 120 degrees apart around gamma. To study how hydrolysis reactions produce mechanical rotation, we observed rotation under an optical microscope to see which of the three sites bound and released a fluorescent ATP analog. Assuming that the analog mimics authentic ATP, the following scheme emerges: (i) in the ATP-waiting state, one site, dictated by the orientation of gamma, is empty, whereas the other two bind a nucleotide; (ii) ATP binding to the empty site drives an approximately 80 degrees rotation of gamma; (iii) this triggers a reaction(s), hydrolysis and/or phosphate release, but not ADP release in the site that bound ATP one step earlier; (iv) completion of this reaction induces further approximately 40 degrees rotation.
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