Analysis of binding interactions between histone core complex and simian virus 40 DNA. A comparison of acetylated versus non-acetylated histone core complexes.

The interactions of acetylated and non-acetylated core complex histones with simian virus 40 (SV40) DNA 1 have been analyzed. A modified filter-binding assay utilizing micrococcal nuclease, which allows quantification of histone octamer binding to DNA has been developed. Using this assay it was determined that both non-acetylated core complex histones ad core complex histones acetylated with acetyl adenylate to levels existing in vivo bind cooperatively to SV40 DNA 1. Although both interactions are cooperative, the magnitude of the cooperativity parameter, omega, is significantly less in the acetylated case. This difference in cooperativity is in contrast to the nearly identical intrinsic association constant, K, observed in both cases.