The Research Of DNA Condensation Dependence On Temperature,Ion Concentration And Force

More and more attentions have been put on DNA condensation, one of the most important reasons is related to the complexity of counterions. Recent experiments have pointed out that effects of temperature and concentration of counterions on the persistence length of DNA are more complex than the theoretical and experimental results before, the anions with different valence also have effects on the conformation and process of DNA condensation. Surprisingly, the DNA condensates become stabler with the temperature increasing. At the same time, single DNA molecule experiment results show that the condensation process is not continuous. For the different condensate conformation of DNA molecules,its de-condensation process also indicates different mechanical properties.Considering these important phenomena, based on the strong correlation model on DNA condensation proposed by us before, by using Monte Carlo method, we have carried out the following tasks:(1) As DNA persistence length strongly depends on counterions concentration,influence of the high concentration of counterions DNA molecule condensation process was explored;(2) Based on the dependence of DNA persistence length on temperature, the influence of the temperature was incorporated into the WLC model, which has strong influences on the DNA condensation process;(3) In order to simulate the single molecule experiment that the DNA molecule condenses with constant force, a constant force was incorporated into our strong correlation model, which can highlight the discontinuous process and was consistentwith the single molecule experiment.Compare computer simulation results with the experimental results, our simulation results were consistent with recent fluoresce experiment and single molecule experiment,indicating that the model set up by us can describe the influence of temperature and counterions concentration properly.