DNA-Endonuclease Complex Dynamics by Simultaneous FRET and Fluorophore Intensity in Evanescent Field.

ABSTRACT: The single-molecule Förster resonance energy transfer (FRET) is a powerful tool to study interactions and conformational changes of biological molecules in the distance range from a few to 10 nm. In this study, we demonstrate a method to augment this range with longer distances. The method is based on the intensity changes of a tethered fluorophore, diffusing in the exponentially decaying evanescent excitation field. In combination with FRET it allowed us to reveal and characterize the dynamics of what had been inaccessible conformations of the DNA-protein complex. Our model system, restriction enzyme Ecl18kI, interacts with a FRET pair-labeled DNA fragment to form two different DNA loop conformations. The DNA-protein interaction geometry is such that the efficient FRET is expected for one

SUBMITTER: Tutkus M 

PROVIDER: S-EPMC5355478 | biostudies-literature | 2017 Mar

REPOSITORIES: biostudies-literature