Measuring single-molecule nucleic acid dynamics in solution by two-color filtered ratiometric fluorescence correlation spectroscopy.

ABSTRACT: This work presents a general method for determining single-molecule intramolecular dynamics in biomolecules by using a reporter fluorophore, whose fluorescence is quenched or partially quenched as a result of intramolecular motion, and a remote observer fluorophore. These fluorophores were excited independently with two different lasers, and the ratio of the two fluorophores' fluorescence was calculated. The time-varying ratio was then filtered to reduce contributions from molecules outside the overlapped laser volume and then correlated. The rates of opening and closing of a DNA hairpin were measured by using both fluorescence correlation spectroscopy and this method for comparison. We found at 50 pM, where molecules were studied one by one as they diffused through the probe volume, we ob

SUBMITTER: Li H 

PROVIDER: S-EPMC521954 | biostudies-literature | 2004 Oct

REPOSITORIES: biostudies-literature