Single molecule measurements of F1-ATPase reveal an interdependence between the power stroke and the dwell duration.
Increases in the power stroke and dwell durations of single molecules of Escherichia coli F(1)-ATPase were measured in response to viscous loads applied to the motor and inhibition of ATP hydrolysis. The load was varied using different sizes of gold nanorods attached to the rotating gamma subunit and/or by increasing the viscosity of the medium using PEG-400, a noncompetitive inhibitor of ATPase activity. Conditions that increase the duration of the power stroke were found to cause 20-fold increases in the length of the dwell. These results suggest that the order of hydrolysis, product release, and substrate binding may change as the result of external load on the motor or inhibition of hydrolysis.
Spetzler
David
D
School of Life Sciences, Arizona State University, P.O. Box 874501, Tempe, Arizona 85287-4501, USA.
Ishmukhametov
Robert
R
Hornung
Tassilo
T
Day
Lixia Jin
LJ
Martin
James
J
Frasch
Wayne D
WD
D000255:Adenosine Triphosphate / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000378:metabolism; D002384:Catalysis / Q000187:drug effects; D002462:Cell Membrane / Q000201:enzymology / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000378:metabolism / Q000494:pharmacology; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000378:metabolism; D006868:Hydrolysis / Q000187:drug effects; D020409:Molecular Motor Proteins / Q000737:chemistry* / Q000378:metabolism; D011092:Polyethylene Glycols / Q000378:metabolism / Q000494:pharmacology; D021122:Protein Subunits / Q000737:chemistry / Q000378:metabolism; D018892:Proton-Motive Force; D006180:Proton-Translocating ATPases / Q000737:chemistry* / Q000378:metabolism; D013997:Time Factors; D014783:Viscosity
D004791:Enzyme Inhibitors; D029968:Escherichia coli Proteins; D020409:Molecular Motor Proteins; D021122:Protein Subunits; D011092:Polyethylene Glycols; D000255:Adenosine Triphosphate; C444660:gamma subunit, F(1) ATPase; D006180:Proton-Translocating ATPases