Stable DNA-protein complexes in eukaryotic chromatin.
Demembranized sperm and somatic nuclei of mammalian origin were extracted with high salt/urea/2-mercaptoethanol, treated with detergents and purified in CsCl density gradients to isolate DNA. Under these conditions a protein component still remained bound to DNA. This stable DNA-protein complex could be reduced to an oligodeoxynucleotide-peptide complex by extensive sequential digestions with DNase I and Pronase E. Chemical and enzymatic treatments of this complex indicated the presence of a phosphoester bond between DNA and a hydroxyamino acid. Two-dimensional tryptic peptide mapping revealed a remarkable similarity among the covalently linked protein components in all types of chromatin studied. These maps differed from the maps of mammalian topoisomerases I and II.
Avramova
Z
Z
Institute of Molecular Biology, Bulgarian Academy of Sciences, Sofia.
Tsanev
R
R
D000818:Animals; D002477:Cells / Q000032:analysis*; D002843:Chromatin / Q000032:analysis*; D002855:Chromatography, Thin Layer; D004247:DNA / Q000378:metabolism*; D005057:Eukaryotic Cells / Q000032:analysis*; D010449:Peptide Mapping; D011506:Proteins / Q000378:metabolism*; D051381:Rats
D002843:Chromatin; D011506:Proteins; D004247:DNA