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Direct observation of tube-like motion of a single polymer chain
Direct observation of tube-like motion of a single polymer chain.
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Tube-like motion of a single, fluorescently labeled molecule of DNA in an entangled solution of unlabeled lambda-phage DNA molecules was observed by fluorescence microscopy. One end of a 16- to 100-micrometer-long DNA was attached to a 1-micrometer bead and moved with optical tweezers. The molecule was stretched into various conformations having bends, kinks, and loops. As the polymer relaxed, it closely followed a path defined by its initial contour. The relaxation time of the disturbance caused by the bead was roughly 1 second, whereas tube-like motion in small loops persisted for longer than 2 minutes. Tube deformation, constraint release, and excess chain segment diffusion were also observed. These observations provide direct evidence for several key assumptions in the reptation model developed by de Gennes, Edwards, and Doi.
Perkins TT, Smith DE, Chu S
Science (New York, N.Y.)
1994-05-06 00:00
264
5160
819-22
Bacteriophage lambda,DNA, Viral,Microscopy, Fluorescence,Nucleic Acid Conformation,Solutions,DNA, Viral,Solutions
Department of Physics, Stanford University, CA 94305
Science
PHS 33289
0036-8075
999
True
8171335
