Title
Exact solutions for kinetic models of macromolecular dynamics
Date Issued
15 May 2008
Access level
metadata only access
Resource Type
journal article
Author(s)
Universidad de California
Publisher(s)
American Chemical Society
Abstract
Dynamic biological processes such as enzyme catalysis, molecular motor translocation, and protein and nucleic acid conformational dynamics are inherently stochastic processes. However, when such processes are studied on a nonsynchronized ensemble, the inherent fluctuations are lost, and only the average rate of the process can be measured. With the recent development of methods of single-molecule manipulation and detection, it is now possible to follow the progress of an individual molecule, measuring not just the average rate but the fluctuations in this rate as well. These fluctuations can provide a great deal of detail about the underlying kinetic cycle that governs the dynamical behavior of the system. However, extracting this information from experiments requires the ability to calculate the general properties of arbitrarily complex theoretical kinetic schemes. We present here a general technique that determines the exact analytical solution for the mean velocity and for measures of the fluctuations. We adopt a formalism based on the master equation and show how the probability density for the position of a molecular motor at a given time can be solved exactly in Fourier-Laplace space. With this analytic solution, we can then calculate the mean velocity and fluctuation-related parameters, such as the randomness parameter (a dimensionless ratio of the diffusion constant and the velocity) and the dwell time distributions, which fully characterize the fluctuations of the system, both commonly used kinetic parameters in single-molecule measurements. Furthermore, we show that this formalism allows calculation of these parameters for a much wider class of general kinetic models than demonstrated with previous methods. © 2008 American Chemical Society.
Start page
6025
End page
6044
Volume
112
Issue
19
Language
English
OCDE Knowledge area
Física atómica, molecular y química
Scopus EID
2-s2.0-44949221589
PubMed ID
Source
Journal of Physical Chemistry B
ISSN of the container
15206106
Sources of information: Directorio de Producción Científica Scopus