Histone IV binding of 3,4-benzpyrene, pyrene, anthracene, and 9-methylanthracene

Ultraviolet absorption, fluorescence excitation and emission, and fluorescence anisotropy demonstrate that the polycyclic aromatic hydrocarbone 3,4-benzpyrene, Pyrene, anthracene, and 9-methylanthracene bind to histone IV after the sow conformational change in the presence of divalent phosphate anion. These hydrocarbons do not bind, within our limits of detection, to histone IV in the diosorderde form at low pH or to the form produced by the fast conformational change when the slow change is prevented. High anisotropy values for the bound hydrocarbon indicate a high degree of aggregation for the histone IV.