Picosecond Torsional Dynamics of DNA

Studies of the structure and conformational dynamics of DNA are central to an understanding of its biological function. Although the long-range segmental motions of the DNA helix have been well characterized by a variety of physical techniques [1], very little is known about the more rapid internal motions in DNA [2–4]. Our objective here is to investigate the torsional (twisting) dynamics of DNA using the techniques of picosecond time-dependent fluorescence depolarization, and to compare the results with the predictions of the elastic model presented by BARKLEY and ZIMM [5]