[Structural transformations of oligonucleosomes from pigeon erythrocyte chromatin].
The methods of velocity sedimentation and circular dichroism have been used to investigate structural rearrangements of pigeon erythrocyte oligonucleosomes isolated after digestion with micrococcal nuclease (oligonucleosomes-M) or pancreatic DNase I (oligonucleosomes-D), in the wide range of ionic strength (mu from 0.005 to 0.5). The electrophoretic analysis of DNA isolated from the oligonucleosomes has revealed internal cuts in the DNA chain of oligonucleosomes-D. In spite of this fact the conformational parameters of DNA in both types of oligonucleosomes are practically indistinguishable, and their optical and hydrodynamic properties vary in a similar way with increasing ionic strength of the solution. The specificity of DNase I action results in the ability of oligonucleosomes-D to form homogeneous associates at mu = 0.065, which seems to be due to the existence of elongated intact ends of linker DNA in oligonucleosomes-D. It has been shown that the integrity of oligonucleosomes-D in a wide range of ionic strength is maintained by histones H1 and H5, because after their dissociation the sedimentation coefficient sharply decreases. The results obtained reveal the multifunctional role of lysine-rich histones and intact linker in the processes of compaction and association of oligonucleosomes.
D000818:Animals; D002843:Chromatin / Q000032:analysis*; D002942:Circular Dichroism; D010856:Columbidae; D004247:DNA / Q000032:analysis; D004587:Electrophoresis, Agar Gel; D004912:Erythrocytes / Q000032:analysis*; D066298:In Vitro Techniques; D009690:Nucleic Acid Conformation; D009707:Nucleosomes / Q000032:analysis*; D009841:Oligonucleotides / Q000032:analysis*
D002843:Chromatin; D009707:Nucleosomes; D009841:Oligonucleotides; D004247:DNA
Strukturnye prevrashcheniia oligonukleosom khromatina éritrotsitov golubia.