High energy radiation-induced crosslinking of histone octamer complexes

Calf thymus histone octamer complexes were irradiated in the native state in N2O-saturated dilute aqueous solution (0.5 g/l, pH 9, [NaClO4] = 1 -4 mol/l) with 50 or 100 ns pulses of 16 MeV electrons or 60Co-gamma-rays. Time resolved light scattering measurements and optical absorption measurements yielded the following: the octamers underwent a volume contraction due to intra-complex-crosslinking induced by the attack of OH-radicals. Crosslinking proceeded to a certain extent via 2,2'-biphenol coupling as inferred from product analyses.