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The characterization of a novel dendritic system for gene delivery by isothermal titration calorimetry
Author(s) -
Coles Daniel J.,
Yang Shu,
Minchin Rodney F.,
Toth Istvan
Publication year - 2008
Publication title -
peptide science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/bip.21019
Subject(s) - isothermal titration calorimetry , dendrimer , chemistry , cell penetrating peptide , polylysine , dna , biophysics , titration , calorimetry , peptide , crystallography , polymer chemistry , stereochemistry , biochemistry , thermodynamics , physics , biology
Understanding the nature of binding of polycationic dendrimers to DNA provides useful information on their role in gene delivery. In the present study, we have characterized the interaction of several peptide‐based polycationic dendrimers with salmon sperm DNA using isothermal titration calorimetry. The dendrimers consisted of the cell penetrating peptide TAT, a nuclear localization signal peptide and dendritic polylysine. The binding affinity and thermodynamic parameters were found to increase as the number of positive charges on the dendrimer increased, indicating that ionic interactions were the major binding forces between the two molecules. The effect of acidic pH (3.2) compared to a more neutral pH (7.2) was also examined. The binding affinity was stronger at the lower pH but precipitation of the complex was more prominent at pH 7.2 which was shown by large enthalpies. The results indicate that our dendrimers are forming stable complexes with DNA. © 2008 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 90: 651–654, 2008. This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com