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E Theofanidou, T J Su, J Arlt, D T Dryden, W J Hossack, J Crain, and W C Poon (2004)
Study of DNA deformation under flow using optical tweezers
In: Optical Trapping and Optical Micromanipulation, edited by Dholakia, K. and Spalding, G. C., pages 712–723.
We have observed a latency time (tau) of the order 10 s in the
spermidine-induced condensation of YOYO-1-labelled DNA in flow. Higher
flow speeds, longer DNA and higher salt all led to an increase in tau.
We propose that two effects may be relevant to these observations (1)
the competition between spermidine and YOYO-1 for DNA binding sites,
and (2) the bending of DNA upon spermidine binding, so that
flow-induced straightening of the DNA weakens spermidine's affinity for
DNA. Moreover, literature data on the mechanical properties of
condensed DNA chains suggest that the hydrodynamic drag forces in our
experiments should indeed significantly perturb condensation kinetics.
Conference on Optical Trapping and Optical Micromanipulation, AUG 02-06, 2004 Denver, CO