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Folding transition into a loosely collapsed state in plasmid DNA as revealed by single‐molecule observation
Author(s) -
Sato Yuko T.,
Hamada Tsutomu,
Kubo Koji,
Yamada Ayako,
Kishida Tsunao,
Mazda Osam,
Yoshikawa Kenichi
Publication year - 2005
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/j.febslet.2005.04.072
Subject(s) - dna , crystallography , molecule , spermine , biophysics , transition (genetics) , chemistry , single molecule experiment , plasmid , conformational change , brownian motion , folding (dsp implementation) , chemical physics , stereochemistry , biology , physics , biochemistry , organic chemistry , quantum mechanics , gene , electrical engineering , enzyme , engineering
The conformational transition of a plasmid DNA, pGEG.GL3 (12.5 kbp, circular), induced by spermine(4+) was studied through the observation of individual DNA by fluorescence microscopy. We deduced the change in the hydrodynamic radius R H from an analysis of the Brownian motion of single DNA molecules. R H decreases in a continuous manner with an increase in spermine(4+), in contrast to the large discrete on/off change for long linear DNA. Just after the transition to the collapsed state, a small number of DNA molecules tend to form an assembly, which disperses in the bulk solution without precipitation.