title: Experimental evidence for asymmetrical shielding of nucleosomal DNA by histones.
abstract: Electron spin resonance study of Mn (II) binding to chromatin and derivatives, including core particles, shows that Mn (II) is a good probe for testing the overall electrostatic balance of the nucleoproteic complex as well as DNA accessibility. Experimental results are in good agreement with a recent model proposed (Mirzabekov A. D. and Rich A. (1979) Proc. Natl. Acad. Sci. USA 76, 1118-1121), for the core particle, in which an asymmetrical shielding of DNA by the protein core is assumed. Furthermore, it was found that the histone H1 hinders a number of charges on the linker DNA in a proportion equal to the net positive charge of the histone itself. This result is interpreted as due to a tighter interaction between the linker DNA and the core histones in the presence of histone H1.
mesh_terms: D000818:Animals; D001665:Binding Sites; D002417:Cattle; D002645:Chickens; D002843:Chromatin / Q000648:ultrastructure; D004247:DNA / Q000032:analysis*; D003852:Deoxyribonucleoproteins / Q000032:analysis; D004578:Electron Spin Resonance Spectroscopy; D004912:Erythrocytes / Q000032:analysis; D006657:Histones / Q000032:analysis*; D008099:Liver / Q000032:analysis; D008345:Manganese; D009707:Nucleosomes / Q000648:ultrastructure*; D051381:Rats; D013950:Thymus Gland
chemical_list: D002843:Chromatin; D003852:Deoxyribonucleoproteins; D006657:Histones; D009707:Nucleosomes; D008345:Manganese; D004247:DNA