Marked difference in conformational fluctuation between giant DNA molecules in circular and linear forms

We performed monomolecular observations on linear and circular giant DNAs (208 kbp) in an aqueous solution by the use of fluorescence microscopy. The results showed that the degree of conformational fluctuation in circular DNA was ca. 40% less than that in linear DNA, although the long-axis length o...

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Veröffentlicht in:The Journal of chemical physics 2015-04, Vol.142 (14), p.145101-145101
Hauptverfasser: Iwaki, Takafumi, Ishido, Tomomi, Hirano, Ken, Lazutin, Alexei A, Vasilevskaya, Valentina V, Kenmotsu, Takahiro, Yoshikawa, Kenichi
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Sprache:eng
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Zusammenfassung:We performed monomolecular observations on linear and circular giant DNAs (208 kbp) in an aqueous solution by the use of fluorescence microscopy. The results showed that the degree of conformational fluctuation in circular DNA was ca. 40% less than that in linear DNA, although the long-axis length of circular DNA was only 10% smaller than that of linear DNA. Additionally, the relaxation time of a circular chain was shorter than that of a linear chain by at least one order of magnitude. The essential features of this marked difference between linear and circular DNAs were reproduced by numerical simulations on a ribbon-like macromolecule as a coarse-grained model of a long semiflexible, double-helical DNA molecule. In addition, we calculated the radius of gyration of an interacting chain in a circular form on the basis of the mean field model, which provides a better understanding of the present experimental trend than a traditional theoretical equation.
ISSN:0021-9606
1089-7690
DOI:10.1063/1.4916309