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- Title
Chemomechanical coupling in F<sub>1</sub>-ATPase revealed by simultaneous observation of nucleotide kinetics and rotation.
- Authors
Nishizaka, Takayuki; Oiwa, Kazuhiro; Noji, Hiroyuki; Kimura, Shigeki; Muneyuki, Eiro; Yoshida, Masasuke; Kinosita, Kazuhiko
- Abstract
F1-ATPase is a rotary molecular motor in which unidirectional rotation of the central ? subunit is powered by ATP hydrolysis in three catalytic sites arranged 120° apart around ?. 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 ?, is empty, whereas the other two bind a nucleotide; (ii) ATP binding to the empty site drives an ~80° rotation of ?; (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 ~40° rotation.
- Subjects
HYDROLYSIS; ADENOSINE triphosphate; NUCLEOTIDES; ADENINE nucleotides; PHOSPHATES; MOLECULAR biology
- Publication
Nature Structural & Molecular Biology, 2004, Vol 11, Issue 2, p142
- ISSN
1545-9993
- Publication type
Article
- DOI
10.1038/nsmb721