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Elongational flow studies of the conformation of DNA molecules in the globular state
Author(s) -
Wakabayashi Kouki,
Sasaki Naoki,
Hikichi Kunio
Publication year - 2000
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/(sici)1097-4628(20000523)76:8<1351::aid-app16>3.0.co;2-l
Subject(s) - flow birefringence , polyethylene glycol , birefringence , molecule , materials science , globular cluster , polymer chemistry , dna , anisotropy , peg ratio , polymer , chemistry , crystallography , organic chemistry , optics , composite material , physics , biochemistry , finance , quantum mechanics , galaxy , economics
Elongational flow‐induced birefringence of a T4‐phage DNA aqueous solution was measured with changing NaCl and polyethylene glycol (PEG) concentrations. DNA molecules are known to manifest a coil–globule transition with increasing PEG concentration. At certain PEG concentrations near the critical concentration of the transition, the globular DNA solution, which was expected to be nonbirefringent, showed flow‐induced birefringence. Strain‐rate dependence of the birefringence intensity, having a critical strain rate, was similar to that of the flexible polymer chain that manifests the coil–stretch transition. The flow‐induced birefringence pattern, however, suggested that the globular DNA molecules were rigid and optically anisotropic. At the critical strain rate, the globular DNA molecules in the solution of the particular PEG concentration were considered to collapse nonadiabatically to an optically anisotropic and mechanically rigid conformation. The overall shape of the collapsed conformation of the globular DNA was estimated to be an ellipsoid with an aspect ratio of about 0.7. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 76: 1351–1358, 2000