DNA Conformation in Aqueous Salt Solution Depends on the Type of Salt Anion

摘要

The effect of singly charged anions F~-, Cl~-, Br~-, I~-, NO_3~-, ClO_4~, SCN~-, and CH_3COO~- on the size and thermodynamic rigidity of the DNA molecule in solution was studied by viscometry and flow birefringence measurements over a wide range of ionic strength at various temperatures. It was shown that the persistent DNA length is independent of the type of salt anion throughout the ionic strength range, and the change in the DNA size (as determined by the change in the characteristic viscosity) is determined by the influence of the anions and their hydration on the long-range interactions in the macromolecule. The possible causes of the observed phenomenon and the role of structural changes in water during the anion hydration were discussed.