Video light microscopy of 670-kb DNA in a hanging drop: shape of the envelope of DNA
| Autor: | Philip Serwer, Renee A. Harris, A. Estrada |
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| Rok vydání: | 1995 |
| Předmět: |
Conformational change
Materials science Biophysics Molecular physics Protein filament chemistry.chemical_compound Random Allocation Ethidium Microscopy Bacteriophages Computer Simulation Electrophoresis Agar Gel Base Composition Microscopy Video Drop (liquid) Intermolecular force Random walk Random coil Molecular Weight Crystallography chemistry Microscopy Fluorescence DNA Viral Nucleic Acid Conformation DNA Research Article |
| Zdroj: | Biophysical journal. 69(6) |
| ISSN: | 0006-3495 |
| Popis: | Although its conformation has not been observed directly, double-stranded DNA in solution is usually assumed to be randomly coiled at the level of the DNA double helix. By video light microscopy of ethidium-stained DNA at equilibrium in a nonturbulent hanging drop, in the present study, the 670 kb linear bacteriophage G DNA is found to form a flexible filament that has on average 17 double helical segments across its width. This flexible filament 1) has both asymmetry and dimensions expected of a random coil and 2) has ends that move according to the statistics expected of a random walk. After unraveling the flexible filament-associated DNA double helix near the surface of a hanging drop, recompaction occurs without perceptible rotation of the DNA. Both conformational change and intermolecular tangling of the DNA are observed when G DNA undergoes nondiffusive motion in a hanging drop. The characteristics of the G DNA flexible filament are explained by the assumption that the flexible filament is a random coil of double helical segments that are unperturbed by motion of the suspending medium. |
| Databáze: | OpenAIRE |
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