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Studies of DNA supercoiling in vivo and in vitro [electronic resource].

Published
Washington, D.C. : United States. Dept. of Energy, 1990.
Oak Ridge, Tenn. : Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy.
Physical Description
Pages: (239 pages) : digital, PDF file
Additional Creators
Lawrence Berkeley National Laboratory, United States. Department of Energy, and United States. Department of Energy. Office of Scientific and Technical Information
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Summary
This thesis describes a number of diverse experiments whose common theme is to elaborate some aspect of DNA supercoiling. The torsion elastic constant of DNA is measure as a function of superhelix density using the technique of picosecond Time Resolved Fluorescence Polarization Anisotropy (FPA) of intercalated ethidium bromide. The results agree with theories which predict that the anisotropy decay should vary with the square root of the relative viscosity. This experiment furthermore demonstrates a sensitivity of FPA to a change in torsion elastic constant of less than 10%. A number of covalently closed DNA samples, ranging in superhelix density from = [minus]0.123 to [plus]0.042, are then examined. A novel method for measuring changes in local supercoiling on a large PNA molecule which is sensitive to changes in supercoiling of regions of chromosomal DNA as short as 1 kilobase in length is presented. Study of chromosomal supercoiling regulating anaerobic gene expression in the facultative photosynthetic bacterium, Rhodobacter capsulatus showed that no stable change in chromosomal supercoiling upon a shift from aerobic respiratory growth to anaerobic photosynthetic conditions. Studies to detect transient changes in DNA supercoiling indicate that DNA downstream from heavily transcribed genes for the photosynthetic reaction center are relaxed or perhaps overwound upon the induction of photosynthetic metabolism. These results are interpreted in terms of the twin domain model of transcriptional supercoiling.
Report Numbers
E 1.99:lbl-32809
lbl-32809
Subject(s)
Other Subject(s)
Note
Published through SciTech Connect.
10/01/1990.
"lbl-32809"
"DE93002556"
Cook, D.N.
Funding Information
AC03-76SF00098
View MARC record | catkey: 13812959