Effects of pH on the stability of chromatin core particles.
Chromatin core particles near physiological ionic strength undergo a reversible transition induced by changes in pH near neutrality. While sedimentation studies indicate no significant effect on size or shape, changes in tyrosine fluorescence anisotropy and in circular dichroism suggest a somewhat looser structure at high pH. Further support of this suggestion is given by high salt dissociation experiments; at pH 8 core particles begin to show changes at lower salt concentration than at pH 6. The pH transition appears unaffected by the presence of Mg2+ but can be blocked by crosslinking of the histones. A possible relationship is suggested between this transition and increases in intracellular pH which correlate with enhancement in several aspects of cellular activity including DNA replication.
D000818:Animals; D002645:Chickens; D002843:Chromatin / Q000648:ultrastructure*; D002942:Circular Dichroism; D004120:Dimethyl Suberimidate; D004912:Erythrocytes / Q000032:analysis; D005454:Fluorescence Polarization; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D009994:Osmolar Concentration
D002843:Chromatin; D004120:Dimethyl Suberimidate