In physiological salt conditions the core proteins of the nucleosomes in large chromatin fragments denature at 73 degrees C and the DNA unstacks at 85 degrees C.

Previous studies of chromatin melting had been done at low salt concentrations to maintain optically clear solutions permitting observation of hyperchromic effects that accompany the unstacking of bases in DNA. Scanning calorimetry does not require clear solutions and so allowed more nearly physiological levels of salt to be used in the present work. HeLa… CONTINUE READING