In this paper we have studied the kinetics of ψ-DNA structure formation induced by histone H1 and H1 peptides containing the C-terminal domain, namely the CTB peptide, obtained by thrombin digestion, and the CNBS peptide, derived from N-bromosuccinimide treatment of H1. The time course for the formation of the ψ structure has been followed by measuring the changes in ellipticity at 270 nm as a function of time under different experimental conditions. In all cases studied here, we have observed the existence of two elementary processes: one fast, the other slow. Kinetic experiments performed with high molecular weight DNA showed that the greater the salt concentration, the higher was the apparent rate of ψ structure formation. In complexes formed with sonicated DNA and H1, CNBS and CTB, we observed that the greater the content of the C-terminal domain, the higher was the apparent rate at which the final ψ structure was reached. Thus, the presence of increasing amounts of either salt or C-terminal domain facilitates the formation of the ψ structure. The molecular basis for these phenomena is discussed. The influence of the order of addition of the different components of the complex on the kinetics of ψ structure induction is also studied. © 1989.
|Publication status||Published - 1 Jan 1989|
- DNA structure, ψ-
- H1 domain
- Histone H1