A simple explanation of the electrostatics of the B-to-Z transition of DNA.
Whereas the phosphates of B-DNA jut out into the solution, those of Z-DNA, being closer to DNA matter, are less subject to electrostatic screening by counterions. We present simple planar models of B- and Z-DNA that reflect these geometric features. The ionic strength dependence of the difference in the Poisson-Boltzmann electrostatic free energy of the models agrees with that measured by Pohl [Pohl, F. M. (1983) Cold Spring Harbor Symp. Quant. Biol. 47, 113-118]. This indicates that the electrostatics of the B-to-Z transition are primarily controlled by a qualitative geometrical difference and not by details of the DNA geometry or by complex electrostatic properties of the ionic solution.
Guéron
M
M
Groupe de Biophysique, Ecole Polytechnique, Palaiseau, France.
Demaret
J P
JP
D004247:DNA / Q000737:chemistry*; D004563:Electrochemistry; D009690:Nucleic Acid Conformation; D010710:Phosphates / Q000737:chemistry; D013816:Thermodynamics
D010710:Phosphates; D004247:DNA