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Histone‐induced conformational changes in DNA as probed by quasi‐elastic light scattering
Author(s) -
Wun K. L.,
Prins W.
Publication year - 1975
Publication title -
biopolymers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/bip.1975.360140109
Subject(s) - chemistry , histone , dna , dna supercoil , chromatin , dynamic light scattering , histone h1 , crystallography , aqueous solution , nucleosome , biophysics , biochemistry , physics , dna replication , quantum mechanics , nanoparticle , biology
Quasi‐elastic light scattering as measured by intensity fluctuation (self‐beat) spectroscopy in the time domain can be profitably used to follow both the translational diffusion D and the dominant internal flexing mode τ int of DNA and its complexes with various histones in aqueous salt solutions. Without histones, DNA is found to have D = 1.6 × 10 −8 cm 2 /sec and τ int ≅ 5 × 10 −4 sec in 0.8 M NaCl, 2 M urea at 20°C. Total histone as well as fraction F2A induce supercoiling ( D = 2.6 × 10 −8 cm 2 /sec, τ int ≅ 2.8 × 10 −4 sec) whereas fraction F1 induces uncoiling ( D = 1.0 × 10 −8 cm 2 /sec, τ int ≅ 9.4 × 10 −4 sec). Upon increasing the salt concentration to 1.5 M the DNA–histone complex dissociates ( D = 1.8 × 10 −8 cm 2 /sec). Upon decreasing the salt concentration to far below 0.8 M , the DNA–histone complex eventually precipitates as a chromatin gel.