Computer Simulation on the Compaction of Chromatin Fiber Induced by Salt

摘要

We present a computer simulation on the compaction of 30-nanometer chromatin fiber induced by salt. The nucleosome is represented as rigid oblate ellipsoids without consideration of DNA-histone wrapping conformation. It is found that equilibrium conformations of multi-nucleosome chains at physiological ionic concentrations are more or less random "zig-zag" structures. Moreover, the diameter, the linear mass density and the persistence length of fiber show a strong dependence on the ion strength. The computational results show us that decreasing the salt strength from 0.15M to 0.01M leads to an increase in the diameter and the linear mass density and a decrease in the persistence length.