Biopolymers and cell. 1986. Volume 2. № 1. 39 - 44, 55
S. N. Khrapunov, A. V. Slvolob, N. E. Kucherenko
THE PECULIARITIES OF THE HI HISTONE-DNA INTERACTION
Summary
The complexes of HI histone from the calf thymus with DNA are studied. Structural changes within a molecule of HI histone and its binding with DNA are registered by the fluorescence of the single tyrosine residue in HI whereas the changes in compactination of DNA are registered turbidimetrically. Association constants of the HI histone globular part with DNA were found on the basis of fluorescence measu¬rements at the different concentration of salt and urea. It is shown that physio¬logical ionic strength induces compactization of DNA, folding of the globular part of HI histone and a sharp decrease of its binding with DNA. The DNA compacti¬zation does not depend on the urea presence in the solution. It is possible to conclude that the globular part of HI histone is not involved in DNA compactization in chromatin. The role of various structural regions of histone HI in chromatin structure stabilization is discussed.