[Structure of histone fragments and their models. I. Structural features of N-terminal oligopeptides of histone H4].

Circular dichroism (CD) and infrared spectroscopy (IRS) studies of aqueous solutions of fourth N-terminal peptides of histone H4 with different chain length were carried out under various conditions. It was shown that all studied peptides had conformation of extended left-handed helix as well as poly-1-proline II at the acidic and neutral pH, in moderate ionic strength (0,15), in 80% ethanol, 0,2 M sodium dodecylsulphate, in 8 M urea and 5 M guanidinum hydrochloride. This conformation was changed by raising temperature, under transition to the range of basic pH and in the concentrated solutions of CaCl2 (5M).