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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 36: Biopolymers and Biological Systems

CPP 36.5: Vortrag

Freitag, 29. Februar 2008, 11:30–11:45, C 264

Cyclization of short DNA fragments: the effects of electrostatic interactions — •A. G. Cherstvy¹ and R. Everaers² — ¹Theorie-II, IFF, FZ Juelich, D-52425 Juelich, Germany — ²Ecole Normale Superieure de Lyon, 46 Allee d'Italie, 69364 Lyon Cedex 07, France

Cyclization of short DNA fragments is known to be a reliable method for measuring the elastic response of DNA molecules to twisting and bending [1]. Although the DNA is one of the most highly charged biopolymers known in nature, the standard theories developed for calculation of the ring formation probabilities by semiflexible polymers [2] neglect completely the electrostatic interactions along DNA chain. We show how the Shimada-Yamakawa theory for DNA cyclization factors [2] is modified due to the presence of charges on DNA. We also study [3] to which extent the phenomenon of Manning's conterion condensation on a straight highly charged cylinder [4] will differ for a DNA ring. We are interested also how the Odijk-Skolnick-Fixman theory of electrostatic persistence of weakly bent rod-like polyelectrolytes [5] will be modified for small circles of DNA.

[1] K. Rippe, et al., Trends Biochem. Sci., 20, 500 (1995). [2] J. Shimada and H. Yamakawa, Macromol., 17 689 (1984). [3] A. G. Cherstvy and R. Everaers, work in preparation. [4] G. S. Manning, J. Phys. Chem. B, 111 8554 (2007). [5] T. Odijk, J. Pol. Sci., 15 477 (1977).