Folding transition into a loosely collapsed state in plasmid DNA as revealed by single-molecule observation.
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.
Sato
Yuko T
YT
Department of Physics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan.
Hamada
Tsutomu
T
Kubo
Koji
K
Yamada
Ayako
A
Kishida
Tsunao
T
Mazda
Osam
O
Yoshikawa
Kenichi
K
D004247:DNA / Q000737:chemistry* / Q000378:metabolism*; D007834:Lasers; D009690:Nucleic Acid Conformation; D010957:Plasmids / Q000737:chemistry* / Q000378:metabolism*
D004247:DNA