Department of Physics Papers

Document Type

Journal Article

Date of this Version

8-2006

Publication Source

The Journal of Physical Chemistry Part B

Volume

110

Issue

24

Start Page

17260

Last Page

17267

DOI

10.1021/jp0630673

Abstract

The tethered particle motion (TPM) technique involves an analysis of the Brownian motion of a bead tethered to a slide by a single DNA molecule. We describe an improved experimental protocol with which to form the tethers, an algorithm for analyzing bead motion visualized using differential interference contrast microscopy, and a physical model with which we have successfully simulated such DNA tethers. Both experiment and theory show that the statistics of the bead motion are quite different from those of a free semiflexible polymer. Our experimental data for chain extension versus tether length fit our model over a range of tether lengths from 109 to 3477 base pairs, using a value for the DNA persistence length that is consistent with those obtained under similar solution conditions by other methods. Moreover, we present the first experimental determination of the full probability distribution function of bead displacements and find excellent agreement with our theoretical prediction. Our results show that TPM is a useful tool for monitoring large conformational changes such as DNA looping.

Copyright/Permission Statement

This document is the unedited Author’s version of a Submitted Work that was subsequently accepted for publication in The Journal of Physical Chemistry B, copyright © 2006 American Chemical Society after peer review.

Included in

Physics Commons

Share

COinS
 

Date Posted: 01 May 2017

This document has been peer reviewed.