Determination of torque generation from the power stroke of Escherichia coli F1-ATPase.
The torque generated by the power stroke of Escherichia coli F(1)-ATPase was determined as a function of the load from measurements of the velocity of the gamma-subunit obtained using a 0.25 micros time resolution and direct measurements of the drag from 45 to 91 nm gold nanorods. This result was compared to values of torque calculated using four different drag models. Although the gamma-subunit was able to rotate with a 20x increase in viscosity, the transition time decreased from 0.4 ms to 5.26 ms. The torque was measured to be 63+/-8 pN nm, independent of the load on the enzyme.
Hornung
Tassilo
T
School of Life Sciences, Arizona State University, P.O. Box 874501, Tempe, AZ 85287-4501, USA.
Ishmukhametov
Robert
R
Spetzler
David
D
Martin
James
J
Frasch
Wayne D
WD
D004926:Escherichia coli / Q000201:enzymology*; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000378:metabolism*; D007700:Kinetics; D021122:Protein Subunits / Q000737:chemistry / Q000378:metabolism; D006180:Proton-Translocating ATPases / Q000737:chemistry / Q000378:metabolism*; D019415:Torque
D029968:Escherichia coli Proteins; D021122:Protein Subunits; D006180:Proton-Translocating ATPases