Hill coefficient for binding ATP to ATPase DNA packaging motor

Value 1.2 unitless Range: ±0.2 unitless
Organism Bacteriophage phi 29
Reference Chemla YR, Aathavan K, Michaelis J, Grimes S, Jardine PJ, Anderson DL, Bustamante C. Mechanism of force generation of a viral DNA packaging motor. Cell. 2005 Sep 9 122(5):683-92.PubMed ID16143101
Method a single stalled packaging complex was attached between a microsphere in an optical trap and a microsphere placed on the end of a micropipette. DNA outside the prohead decreases in length over time as it is reeled into the capsid against a constant external force of approximately 5 pN. ATP concentrations range from 5 to 1000 µM, with ADP and inorganic phosphate (Pi) fixed at 5 µM each (the latter added to ensure a defined free energy of hydrolysis, ?G = ?G0 + kBT ln([ATP]/[ADP][Pi])).
Comments Hill coefficient of 1 implies that the binding of one ATP neither facilitates nor hinders the binding of another ATP.
Entered by Uri M
ID 103171