STATIC CONTRIBUTIONS TO THE PERSISTENCE LENGTH OF DNA AND DYNAMIC CONTRIBUTIONS TO DNA CURVATURE

Long molecules of DNA have the statistical properties of a worm-like c oil. Deviations from linearity occur both because of small dynamic ben ds induced by thermal motion and from a random distribution of static bends. The latter originate in the different conformations of each of the possible base pair sequences. In this paper a statistical theory o f the persistence length of DNA is developed which includes both stati c and dynamic effects for each base pair sequence, as well as the sequ ence-dependent correlations of bending angles. The result applies to a generic DNA, i.e., the average over an ensemble of all possible seque nces. The theory is also applied to the generation of the average prop erties of curved DNAs by an analytic method that includes dynamic aver aging as well as correlated bends. These results provide information w hich supplements that obtained by others using Monte Carlo methods. Th e additivity relation 1/P = 1/P-s + 1/P-d proposed by Trifonov et al., where P is the persistence length and P-s and P-d are the persistence lengths arising from purely static and dynamic effects, respectively, has been verified to be accurate to better than 0.5%. This is true fo r both a simplified model and one that includes a complete set of stat ic bends at all base pair sequences.