title: Marked difference in conformational fluctuation between giant DNA molecules in circular and linear forms.
abstract: 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.
authors: Faculty of Medicine, Oita University, Hasama-cho Idaigaoka 1-1, Yufu, Oita 879-5593, Japan.
authors: Takafumi
authors: T
authors: Iwaki
authors: AIST Shikoku, Hayashi-cho 2217-14, Takamatsu, Kagawa 761-0395, Japan.
authors: Tomomi
authors: T
authors: Ishido
authors: AIST Shikoku, Hayashi-cho 2217-14, Takamatsu, Kagawa 761-0395, Japan.
authors: Ken
authors: K
authors: Hirano
authors: A.N. Nesmeyanov Institute of Organoelement Compounds, Vavilova Street 28, V-334, GSP-1, Moscow 119991, Russia.
authors: Alexei A
authors: AA
authors: Lazutin
authors: A.N. Nesmeyanov Institute of Organoelement Compounds, Vavilova Street 28, V-334, GSP-1, Moscow 119991, Russia.
authors: Valentina V
authors: VV
authors: Vasilevskaya
authors: Faculty of Life and Medical Science, Doshisha Universiy, Tatara Miyakodani 1-3, Kyotanabe, Kyoto 610-0321, Japan.
authors: Takahiro
authors: T
authors: Kenmotsu
authors: Faculty of Life and Medical Science, Doshisha Universiy, Tatara Miyakodani 1-3, Kyotanabe, Kyoto 610-0321, Japan.
authors: Kenichi
authors: K
authors: Yoshikawa
mesh_terms: D022202:Chromosomes, Artificial, Bacterial / Q000235:genetics; D004270:DNA, Circular / Q000737:chemistry*; D004058:Diffusion; D008958:Models, Molecular; D009010:Monte Carlo Method; D009690:Nucleic Acid Conformation
chemical_list: D004270:DNA, Circular