Radial distribution function for semiflexible polymers confined in microchannelsP. Levi and K. Mecke
Institut für Theoretische Physik, Universität Erlangen-Nürnberg - Staudtstraße 7, 91058 Erlangen, Germany
received 22 December 2006; accepted in final form 12 March 2007; published May 2007
published online 11 April 2007
An analytic expression is derived for the distribution of the end-to-end distance of semiflexible polymers in external potentials to elucidate the effect of confinement on the mechanical and statistical properties of biomolecules. For parabolic confinement the result is exact, whereas for realistic potentials a self-consistent ansatz is applied, so that is given explicitly even for hard-wall confinement. The theoretical result is in good quantitative agreement with fluorescence microscopy data for actin filaments confined in rectangularly shaped microchannels. This allows an unambiguous determination of persistence length LP and the dependence of statistical properties such as Odijk's deflection length on the channel width D. It is shown that neglecting the effect of confinement leads to a significant overestimation of bending rigidities for filaments.
87.15.-v - Biomolecules: structure and physical properties.
36.20.Ey - Conformation (statistics and dynamics).
05.20.-y - Classical statistical mechanics .
© Europhysics Letters Association 2007