OPTICAL ABSORBANCE AND OPTICAL ROTATORY DISPERSION STUDIES ON CALF THYMUS NUCLEOHISTONE

Optical absorption and optical rotatory dispersion studies of native nucleohistone and of nucleohistone fully or partially and selectively dissociated into DNA and histone, show that (1) the conformation of whole histone mixtures as well as of individual histone fractions is highly ionic strength dependent and that the conformation of histone in association with DNA approximates that of free histone in solutions of high ionic strength; (2) the conformation of DNA in native nucleohistone is altered as compared to free DNA; and (3) neither lysinerich histone I nor non-histone protein is responsible for the conformational characteristics of DNA in nucleohistone. © 1969.