Video light microscopy of 670-kb DNA in a hanging drop: shape of the envelope of DNA

Biophysical Journal
P SerwerR A Harris

Abstract

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.

Citations

May 19, 2001·Electrophoresis·G A GriessP Serwer
Feb 3, 1999·Annual Review of Genetics·S Casjens
Nov 30, 2007·Journal of Microscopy·Philip SerwerGary A Griess
Nov 28, 2001·Journal of Structural Biology·S HuangP Serwer
May 8, 2007·Electrophoresis·Philip SerwerStephen C Hardies
Apr 11, 2020·Viruses·Philip Serwer, Elena T Wright
Jan 21, 2004·Journal of Microscopy·H WangP Serwer

❮ Previous
Next ❯

Related Concepts

Related Feeds

Cajal Bodies & Gems

Cajal bodies or coiled bodies are dense foci of coilin protein. Gemini of Cajal bodies, or gems, are microscopically similar to Cajal bodies. It is believed that Cajal bodies play important roles in RNA processing while gems assist the Cajal bodies. Find the latest research on Cajal bodies and gems here.

Bacteriophage: Phage Therapy

Phage therapy uses bacterial viruses (bacteriophages) to treat bacterial infections and is widely being recognized as an alternative to antibiotics. Here is the latest research.