Open AccessConformation of DNA in chromatin core particles containing poly(dAdT)·poly(dAdT) studied by31P NMR spectroscopy
Author(s) -
Robert T. Simpson,
Heisaburo Shindo
Publication year - 1979
Publication title -
nucleic acids research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 9.008
H-Index - 537
eISSN - 1362-4954
pISSN - 0305-1048
DOI - 10.1093/nar/7.2.481
Subject(s) - chromatin , particle (ecology) , dna , nuclear magnetic resonance spectroscopy , spectroscopy , histone , core (optical fiber) , crystallography , biology , biophysics , analytical chemistry (journal) , stereochemistry , materials science , chemistry , biochemistry , physics , chromatography , ecology , quantum mechanics , composite material
We have prepared semi-synthetic chromatin core particles from a complex of chicken erythrocyte inner histones (H2A, H2B, H3 and H4) with double-stranded poly(dAdT).poly(dAdT) and studied the conformation of the phosphodiester backbone using 31P NMR at 109.3 MHz. At 20 degrees C, the core particle spectrum is fit well by a single Lorenzian distribution with a line width of 110 Hz. This signal is significantly broader than that for the 145 base pair poly(dAdT).poly(dAdT) alone; the latter consists of two resonances, approximately equal in intensity, with average line width 41 Hz. Major changes in the spectrum ensue on heating the core particle preparation. In conjunction with other results (1) these data suggest four states for the core particle at increasing temperatures. Additionally, analysis of the spectrum of the unmelted core particle and its differences from protein-free DNA of the same length suggests that the conformation of the phosphodiester backbone and/or its interactions with histones along the length of the core particle DNA segment may not be uniform.