FREE-ENERGY OF AN ARBITRARY CHARGE-DISTRIBUTION IMBEDDED IN COAXIAL CYLINDRICAL DIELECTRIC CONTINUA - APPLICATION TO CONFORMATIONAL PREFERENCES OF DNA IN AQUEOUS-SOLUTIONS

Theoretical expressions for evaluating the electrostatic contribution to the solvation free energy of macromolecules with cylindrical or quasi-cylindrical symmetry are obtained based on a continuum treatment of the environment. These include provision to consider the detailed spatial charge distribution, the influence of the dielectric boundary, the ion atmosphere, and the dielectric saturation. The theory developed is illustrated with an application to the conformational preferences of DNA in aqueous solutions. It is shown with a discrete spatial charge distribution of DNA that the B form of DNA is favored over both A and Z forms in aqueous solutions at low added salt, thus resolving a contradiction with experiment observed in line charge representations of the double helix. © 1990 American Chemical Society.