DNA Unwrapped (IMAGE) Arizona State University Caption This graphic shows the time elapsed during DNA unwrapping (a) and re-wrapping (b) as measured by FRET analysis. FRET works by measuring the distance between a pair of fluorescent molecules of fluorophores -- one attached to the end of the DNA and the other attached to the histone protein spool around which the DNA "thread" winds and unwinds. Credit Reprinted from: <I>Journal of Molecular Biology</I>, volume 411(2), Tims HS, Gurunathan K, Levitus M, Widom J, Dynamics of nucleosome invasion by DNA binding proteins, pgs 430-48, with permission from Elsevier. Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.