Orientation dependence of single-fluorophore intensity was exploited in order to videotape conformational changes in a protein machine in real time. The fluorophore Cy3 attached to the central subunit of F1-ATPase revealed that the subunit rotates in the molecule in discrete 120°steps and that each step is driven by the hydrolysis of one ATP molecule. These results, unlike those from the previous study under a frictional load, show that the 120° stepping is a genuine property of this molecular motor. The data also show that the rate of ATP binding is insensitive to the load exerted on the rotor subunit.
|Number of pages||5|
|Journal||Proceedings of the National Academy of Sciences of the United States of America|
|Publication status||Published - 2000 Jun 20|
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