THERMAL-DENATURATION OF CHROMATIN AND LYSINE COPOLYMER-DNA COMPLEXES - EFFECTS OF ETHYLENE-GLYCOL

Chromatin was thermally denatured in the presence and absence of 1M ethylene glycol using a technique whereby both the hyperchromism and ellipticity are monitored simultaneously. Model complexes containing poly(L‐Lys) or poly(L‐Lys, L‐Ala, Gly) and DNA were similarly melted in order to assist in interpreting the chromatin results. In both cases a general pattern emerged whereby ethylene glycol perturbed the resultant melting profile, showing increased hyperchromicity, ellipticity, and premelt slope. In addition, ethylene glycol destabilizes and reduces the high melting region of polypeptide‐bound DNA and the extent of higher ordered structure in model complexes and chromatin. These results emphasize the importance of hydrophobic forces in polypeptide–polypeptide and polypeptide–DNA interactions. Copyright © 1979 John Wiley & Sons, Inc.