Voltage dependence of a stochastic model of activation of an alpha helical S4 sensor in a K channel membrane
Files
(Published version)
Date
2011
Authors
Vaccaro, S.
Editors
Advisors
Journal Title
Journal ISSN
Volume Title
Type:
Journal article
Citation
Journal of Chemical Physics, 2011; 135(9):095102-1-095102-9
Statement of Responsibility
S. R. Vaccaro
Conference Name
Abstract
The voltage dependence of the ionic and gating currents of a K channel is dependent on the activation barriers of a voltage sensor with a potential function which may be derived from the principal electrostatic forces on an S4 segment in an inhomogeneous dielectric medium. By variation of the parameters of a voltage-sensing domain model, consistent with x-ray structures and biophysical data, the lowest frequency of the survival probability of each stationary state derived from a solution of the Smoluchowski equation provides a good fit to the voltage dependence of the slowest time constant of the ionic current in a depolarized membrane, and the gating current exhibits a rising phase that precedes an exponential relaxation. For each depolarizing potential, the calculated time dependence of the survival probabilities of the closed states of an alpha helical S4 sensor are in accord with an empirical model of the ionic and gating currents recorded during the activation process.
School/Discipline
Dissertation Note
Provenance
Description
Published online 6 September 2011
Access Status
Rights
© 2011 American Institute of Physics