Stability of strong polyelectrolyte-macroion complexes

We investigate the thermodynamic stability of complexes formed by one semi-flexible charged polymer wrapped around an oppositely charged sphere. Choosing parameters for DNA and histones, we determine all conformational eigen-modes and the corresponding eigen-value spectrum of the complexed chain, from which the free energy of complexation and thus the reaction constant is obtained. The resulting complexation diagram exhibits qualitative agreement with experimental results as a function of salt and DNA/histone concentration.