Interplay between folding/unfolding and helix/coil transitions in giant DNA.
It has been well established that double-stranded DNA undergoes a melting, or helix/coil, transition into a single-stranded coil state with an increase in temperature. On the other hand, it has recently been found that, at a fixed temperature, long DNA, larger than several kilobase pairs, exhibits a discrete transition, or switching, between elongated and folded states, preserving its double-stranded structure, with the addition of various condensation agents, such as alcohol, hydrophilic polymer, multivalent cation, and cationic surfactant. In the present study, we examined the interplay between the folding/unfolding transition and the helix/coil transition in individual giant DNA molecules, by observing the conformation of single molecular chains with fluorescence microscopy. The results indicate that the helix-to-coil transition tightly cooperates with the unfolding transition in DNA.
Mikhailenko
S V
SV
Graduate School of Human Informatics, Nagoya University, Nagoya 464-8601, Japan. sergeyev@genebee.msu.su
Sergeyev
V G
VG
Zinchenko
A A
AA
Gallyamov
M O
MO
Yaminsky
I V
IV
Yoshikawa
K
K
D002942:Circular Dichroism; D004247:DNA / Q000737:chemistry*; D008856:Microscopy, Fluorescence; D009690:Nucleic Acid Conformation; D012997:Solvents; D013050:Spectrometry, Fluorescence; D013056:Spectrophotometry, Ultraviolet; D013696:Temperature
D012997:Solvents; D004247:DNA