title: Interactions of histones and histone peptides with DNA Thermal denaturation and solubility studies.
abstract: The interactions of DNA with the five histone components (H1, H2B, H2A, H3 and H4) and with a number of histone fragments (N-H1 (1--72), C-H1 (73--216), N-H2B (l--59), C-H2B, (63--125), N-H2A (1-39), C-H2A (58--129), N-H4 (1--84) and C-H4 (85--102) have been studied by using the techniques of thermal denaturation and solubility behaviour. Complexes in 10(-3) M phosphate buffer, 2 - 10(-5) M Na(2)-EDTA, pH 7.0 were prepared by the direct mixing method. For lysine-rich histones (H1 and H2B) it has been found that the main characteristics which governs the interaction with DNA are located in the very lysine-rich part of the molecules, i.e. in the C-H1 and N-H2B segments. These regions are also responsible for a cooperative distribution of the histone along the DNA molecules in the artificial complexes. It appears from our studies that the tertiary structure of the moderately, arginine-rich histone (H2A) is an essential feature for its interaction with DNA. The two arginine-rich histones (H3 and H4) complexed with DNA behave in a similar way, both in thermal denaturation and in DNA precipitation. In the case of C-H4, a marked shift of the melting profile has been observed which is correlated with the presence in the peptide of the hydrophilic cluster Lys-Arg-Gln-Gly-Arg-Thr. Our results suggest that large segments rich in lysine and basic clustering within histones give rise to different modes of electrostatic interaction with DNA.
mesh_terms: D000818:Animals; D002417:Cattle; D055598:Chemical Phenomena; D002621:Chemistry; D004247:DNA; D006657:Histones; D006358:Hot Temperature; D009691:Nucleic Acid Denaturation; D009994:Osmolar Concentration; D010446:Peptide Fragments; D011487:Protein Conformation; D012965:Sodium Chloride / Q000494:pharmacology; D012995:Solubility; D013950:Thymus Gland
chemical_list: D006657:Histones; D010446:Peptide Fragments; D012965:Sodium Chloride; D004247:DNA