Comments on selected aspects of nucleic acid electrostatics

Recent experimental, theoretical, and computational developments in the field of nucleic acid electrostatics have brought interesting concepts to the fore. The phosphate charge on the double helix apparently influences its structure. When the charge is neutralized asymmetrically, the resulting force imbalance drives bending toward the neutralized side. When the charge is uniformly neutralized, the force imbalance acts to buckle the helical axis, resulting in a compact tertiary conformation. Sharing of condensed counterions by single strands is a stabilizing factor for formation of the double helix. Sharing of condensed counterions by two double helices causes clustering of DNA and may be a factor in RNA folding. Support for these statements is reviewed.