Biophysical Journal 66: 962-971 (1994)
© 1994 the Biophysical Society

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Podgornik, R Articles by Parsegian, V A Search for Related Content PubMed PubMed Citation Articles by Podgornik, R Articles by Parsegian, V A

Parametrization of direct and soft steric-undulatory forces between DNA double helical polyelectrolytes in solutions of several different anions and cations.

NIDDK, National Institutes of Health, Bethesda, Maryland 20892.

ABSTRACT

Directly measured forces between DNA helices in ordered arrays have been reduced to simple force coefficients and mathematical expressions for the interactions between pairs of molecules. The tabulated force parameters and mathematical expressions can be applied to parallel molecules or, by transformation, to skewed molecules of variable separation and mutual angle. This "toolbox" of intermolecular forces is intended for use in modelling molecular interactions, assembly, and conformation. The coefficients characterizing both the exponential hydration and the electrostatic interactions depend strongly on the univalent counterion species in solution, but are only weakly sensitive to anion type and temperature (from 5 to 50 degrees C). Interaction coefficients for the exponentially varying hydration force seen at spacings less than 10 to 15 A between surfaces are extracted directly from pressure versus interaxial distance curves. Electrostatic interactions are only observed at larger spacings and are always coupled with configurational fluctuation forces that result in observed exponential decay lengths that are twice the expected Debye-Huckel length. The extraction of electrostatic force parameters relies on a theoretical expression describing steric forces of molecules "colliding" through soft exponentially varying direct interactions.

This article has been cited by other articles:

				C. Stanley and D. C. Rau Preferential Hydration of DNA: The Magnitude and Distance Dependence of Alcohol and Polyol Interactions Biophys. J., August 1, 2006; 91(3): 912 - 920. [Abstract] [Full Text] [PDF]

				J. Yang and D. C. Rau Incomplete Ion Dissociation Underlies the Weakened Attraction between DNA Helices at High Spermidine Concentrations Biophys. J., September 1, 2005; 89(3): 1932 - 1940. [Abstract] [Full Text] [PDF]

				Y. Bai, R. Das, I. S. Millett, D. Herschlag, and S. Doniach Probing counterion modulated repulsion and attraction between nucleic acid duplexes in solution PNAS, January 25, 2005; 102(4): 1035 - 1040. [Abstract] [Full Text] [PDF]

				C. M. Wiethoff, M. L. Gill, G. S. Koe, J. G. Koe, and C. R. Middaugh The Structural Organization of Cationic Lipid-DNA Complexes J. Biol. Chem., November 15, 2002; 277(47): 44980 - 44987. [Abstract] [Full Text] [PDF]