Fast dynamics of supercoiled DNA revealed by single-molecule experiments.
The dynamics of supercoiled DNA play an important role in various cellular processes such as transcription and replication that involve DNA supercoiling. We present experiments that enhance our understanding of these dynamics by measuring the intrinsic response of single DNA molecules to sudden changes in tension or torsion. The observed dynamics can be accurately described by quasistatic models, independent of the degree of supercoiling initially present in the molecules. In particular, the dynamics are not affected by the continuous removal of the plectonemes. These results set an upper bound on the hydrodynamic drag opposing plectoneme removal, and thus provide a quantitative baseline for the dynamics of bare DNA.
Crut
Aurélien
A
Kavli Institute of Nanoscience, Faculty of Applied Sciences, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, The Netherlands.
Koster
Daniel A
DA
Seidel
Ralf
R
Wiggins
Chris H
CH
Dekker
Nynke H
NH
D004278:DNA, Superhelical / Q000737:chemistry* / Q000378:metabolism*; D003850:Deoxyribonuclease I / Q000378:metabolism; D009690:Nucleic Acid Conformation; D012399:Rotation
D004278:DNA, Superhelical; D003850:Deoxyribonuclease I