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Biophys J. 1996 Oct;71(4):2064-74.

Binding of ionic ligands to polyelectrolytes.

Author information

1
Department of Pharmaceutical Chemistry, University of California, San Francisco 94143, USA.

Abstract

Ionic ligands can bind to polyelectrolytes such as DNA or charged polysaccharides. We develop a Poisson-Boltzmann treatment to compute binding constants as a function of ligand charge and salt concentration in the limit of low ligand concentration. For flexible chain ligands, such as oligopeptides, we treat their conformations using lattice statistics. The theory predicts the salt dependence and binding free energies, of Mg(2+) ions to polynucleotides, of hexamine cobalt(III) to calf thymus DNA, of polyamines to T7 DNA, of oligolysines to poly(U) and poly(a), and of tripeptides to heparin, a charged polysaccharide. One parameter is required to obtain absolute binding constants, the distance of closest separation of the ligand to the polyion. Some, but not all, of the binding entropies and enthalpies are also predicted accurately by the model.

PMID:
8889181
PMCID:
PMC1233673
DOI:
10.1016/S0006-3495(96)79405-5
[Indexed for MEDLINE]
Free PMC Article

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