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BP: Fachverband Biologische Physik

BP 3: DNA, RNA and Associated Enzymes

BP 3.9: Vortrag

Montag, 22. März 2010, 16:30–16:45, H43

DNA-DNA electrostatic frictional forces: magnitude and biological implications — •Andrey Cherstvy — IFF-2, FZ Jülich, Germany

We estimate theoretically the strength of DNA-DNA electrostatic frictional forces emerging upon dragging one DNA molecule over another one in a close parallel juxtaposition [1]. For ideally helical DNA duplexes, this friction occurs due to correlations in electrostatic potential near DNA surfaces. The latter originate from intrinsic helicity of DNA phosphate charges on the scale of 3.4 nm along DNA axis that produces a positive-negative charge interlocking along the DNA-DNA contact. For realistic, non-ideally helical DNAs, where electrostatic potential barriers become decorrelated due to accumulation of "sequence mismatches" in DNA structure, DNA-DNA frictional forces are strongly impeded. We calculate DNA-DNA frictional forces in both cases and describe their implications for sequence recognition of DNA duplexes that takes place in vivo upon cell division. We also discuss the possibilities of probing DNA-DNA intermolecular interactions in strongly confined DNA superhelical plies as obtained in single-molecule dual optical trap experiments.

[1] A. G. Cherstvy, J. Phys. Chem. B, 113 5350 (2009).