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Cooperativity vs. Phase Transition in a Giant Single DNA Molecule

Iwataki, Toshio and Yoshikawa, Kinichi and Kidoaki, Satoru and Umeno, Daisuke and Kiji, Masami and Maeda, Mizuo (2000) Cooperativity vs. Phase Transition in a Giant Single DNA Molecule. Journal of the American Chemical Society, 122 (41). pp. 9891-9896. ISSN 0002-7863.

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Single-chain observation of giant DNAs grafted with poly(N-isopropylacrylamide) (PNIPAAM) was performed using fluorescence microscopy while changing the solution temperature. The PNIPAAM-grafted DNA was prepared through the intercalation of psoralen-terminated PNIPAAM. Individual DNAs grafted with PNIPAAM exhibit a sharp but continuous transition at around 34 °C, from an elongated coil to a collapsed compact state. It is found that the width of the transition is almost the same between the level of individual DNAs and the level of ensemble DNAs. The unique nature of this transition is discussed in comparison with the discrete nature of the folding transition in native double-strand DNAs. With the addition of spermidine, a trivalent amine, the conformation of individual T4DNAs changes in a markedly discrete manner, on the level of individual giant DNAs, whereas in the ensemble, the size of T4 DNAs changes rather mildly; i.e., the transition appears to occur over a temperature range of 30 degrees. Thus, it is confirmed that the cooperative transition on the DNAs grafted with PNIPAAM exhibits a sharper transition than the change in the ensemble average for the discrete phase transition in native DNAs induced by the polycation.

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Additional Information:© 2000 American Chemical Society Received 21 January 2000 Published online 3 October 2000 Published in print 1 October 2000 We thank Prof. T. Matsuda (Graduate School of Medical Science, Kyushu University) and Dr. Y. Nakayama (Department of Bioengineering, National Cardiovascular Center) for their help in the AFM observation. This study was supported in part by a Grant-in-aid for Scientific Research from the Ministry of Education, Science, Culture, and Sports of Japan.
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Ministry of Education, Culture, Sports, Science and Technology (MEXT)UNSPECIFIED
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Official Citation:Cooperativity vs. Phase Transition in a Giant Single DNA Molecule Toshio Iwataki, Kenichi Yoshikawa, Satoru Kidoaki, Daisuke Umeno, Masami Kiji,, and Mizuo Maeda Journal of the American Chemical Society 2000 122 (41), 9891-9896 DOI: 10.1021/ja000230d
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:75674
Deposited By: Ruth Sustaita
Deposited On:04 Apr 2017 19:13
Last Modified:04 Apr 2017 19:13

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