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Nucleic acid-protein interactions: conformational studies. Progress report, September 1, 1978-August 31, 1981

Technical Report ·
OSTI ID:5579299
High molecular weight chicken erythrocyte chromatin was found not to spontaneously self assemble into native like material after dissociation into 2 M NaCl and reassociation by gradient dialysis. H1/H5 on 200 base pair (bp) mononucleosomes was found to stabilize the linker DNA, as well as core DNA associated with core histones. Mononucleosomes with varying DNA length and H1/H5 content were studied and it was found that H1/H5 stabilizes 30 bp of core DNA. Histone complexes (H3:H4, H2A:H2B and core octamer) were shown to be reversibly renatured after acid denaturation. Solvent and temperature induced conformational transitions of the histone complexes showed that the H3:H4 tetramer was the most flexible complex. Physical-chemical studies on chromatin indicated substantial stabilization of core particle DNA and linker DNA by H1/H5 binding. The difference in conformation of H3:H4 complexes isolated in low and high salt concentrations was shown by serological and circular dichroism analysis. The antibody also reacts with chromatin. A more condensed chromatin was found in HeLa cells where the histones were highly acetylated by butyrate treatment. The effect of acetylation was moderated through the interaction of H1 and HMG proteins. Synthetic chromatins, Poly (dAdT)/sub 2/ or Poly(dGdC)/sub 2/: core histone complexes were shown to have a large degree of conformational flexibility of the polynucleotide, indicating weak binding.
Research Organization:
Brandeis Univ., Waltham, MA (USA)
DOE Contract Number:
AS02-78EV04962
OSTI ID:
5579299
Report Number(s):
DOE/EV/04962-3; ON: DE82007506
Country of Publication:
United States
Language:
English