Interplay between Folding/Unfolding and Helix/Coil Transitions in Giant DNA

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• 作者：Sergey V. Mikhailenko ; Vladimir G. Sergeyev ; Anatoly A. Zinchenko ; Marat O. Gallyamov ; Igor V. Yaminsky ; and Kenichi Yoshikawa
• 刊名：Biomacromolecules
• 出版年：2000
• 出版时间：December 2000
• 年：2000
• 卷：1
• 期：4
• 页码：597 - 603
• 全文大小：171K
• 年卷期：v.1,no.4(December 2000)
• ISSN：1526-4602

文摘

It has been well established that double-stranded DNA undergoes a melting, or helix/coil, transition into asingle-stranded coil state with an increase in temperature. On the other hand, it has recently been foundthat, at a fixed temperature, long DNA, larger than several kilobase pairs, exhibits a discrete transition, orswitching, between elongated and folded states, preserving its double-stranded structure, with the additionof various condensation agents, such as alcohol, hydrophilic polymer, multivalent cation, and cationicsurfactant. In the present study, we examined the interplay between the folding/unfolding transition and thehelix/coil transition in individual giant DNA molecules, by observing the conformation of single molecularchains with fluorescence microscopy. The results indicate that the helix-to-coil transition tightly cooperateswith the unfolding transition in DNA.