SPECTROSCOPY, IMAGING, OTHER TECHNIQUES |
Comparative Energy Measurements in Single Molecule Interactions
Wei Liu 1, Vedrana Montana 2, Vladimir Parpura 3 and Umar Mohideen 4*
1 University of California -Riverside (Present:University of Alabama- Birmingham)
2 Present Address: University of Alabama-Birmingham
3 Present Address: Univeristy of Alabama-Birmingham
4 University of California-Riverside
* To whom correspondence should be addressed. E-mail: umar.mohideen{at}ucr.edu.
Submitted on December 14, 2007
Revised on January 18, 2008
Accepted on 29 February 2008
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Abstract |
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Single molecule experiments have opened promising new avenues of investigations in biology, but the quantitative interpretation of results remains challenging. In particular there is a need for a comparison of such experiments with theoretical methods. We experimentally determine the activation free energy for single molecule interactions between two synaptic proteins syntaxin 1A and synaptobrevin 2, using an atomic force microscope and the Jarzynski equality of non-equilibrium thermodynamics. The value obtained is shown to be reasonably consistent with that from single molecule reaction rate theory. The temperature dependence of the spontaneous dissociation lifetime along with different pulling speeds is used to confirm the approach to the adiabatic limit. This comparison of the Jarzynski equality for intermolecular interactions, extends the procedure for calculation of activation energies in non-equilibrium processes
Key Words:
Activation Free Energy, Atomic Force Microscopy, Jarzynski Equality, Single Molecule Reaction Rate Theory
