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Torsion and bending of nucleic acids studied by subnanosecond time-resolved fluorescence depolarization of intercalated dyes

Millar, D. P. and Robbins, R. J. and Zewail, A. H. (1982) Torsion and bending of nucleic acids studied by subnanosecond time-resolved fluorescence depolarization of intercalated dyes. Journal of Chemical Physics, 76 (4). pp. 2080-2094. ISSN 0021-9606. doi:10.1063/1.443182.

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Subnanosecond time‐resolved fluorescence depolarization has been used to monitor the reorientation of ethidium bromide intercalated in native DNA, synthetic polynucleotide complexes, and in supercoiled plasmid DNA. The fluorescence polarization anisotropy was successfully analyzed with an elastic model of DNA dynamics, including both torsion and bending, which yielded an accurate value for the torsional rigidity of the different DNA samples. The dependence of the torsional rigidity on the base sequence, helical structure, and tertiary structure was experimentally observed. The magnitude of the polyelectrolyte contribution to the torsional rigidity of DNA was measured over a wide range of ionic strength, and compared with polyelectrolyte theories for the persistence length. We also observed a rapid initial reorientation of the intercalated ethidium which had a much smaller amplitude in RNA than in DNA.

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Additional Information:© 1982 American Institute of Physics. Received 28 August 1981; accepted 15 October 1981. This work has benefited tremendously from collaboration with a number of enthusiastic and helpful colleagues at Caltech. Thanks are due to Dr. Michael Becker and Dr. Horace Drew for suggestions and encouragement; to Professor Peter Dervan for gifts of some synthetic polynucleotide samples; and to Dr. Richard Scheller for preparing the supercoiled plasmid DNA. We also thank Professor J. Michael Schurr of the University of Washington for helpful telephone discussions and Professor Mary Barkley of the University of Kentucky for constructive comments. Appreciation is also expressed to the National Science Foundation for partial support of this work under Grant Nos. CHE79-05683 and DMRSl-05034.
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Issue or Number:4
Classification Code:PACS: 87.15.H-, 87.15.M-, 33.50.Dq
Record Number:CaltechAUTHORS:20120717-133015128
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Official Citation:Torsion and bending of nucleic acids studied by subnanosecond time‐resolved fluorescence depolarization of intercalated dyes D. P. Millar, R. J. Robbins, and A. H. Zewail J. Chem. Phys. 76, 2080 (1982);
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:32524
Deposited By: Ruth Sustaita
Deposited On:17 Jul 2012 21:36
Last Modified:09 Nov 2021 21:27

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