TY - JOUR
T1 - Formation of DNA nanoparticles in the presence of novel polyamine analogues
T2 - A laser light scattering and atomic force microscopic study
AU - Vijayanathan, Veena
AU - Thomas, Thresia
AU - Antony, Thomas
AU - Shirahata, Akira
AU - Thomas, T. J.
N1 - Funding Information:
T.A. expresses his deep sense of gratitude to Drs Tom Jovin and Vinod Subramaniam for their help and support for conducting the atomic force microscopic experiments during his tenure as an Alexander von Humboldt Fellow at the Max Plank Institute for Biophysical Chemistry. This work was supported by Public Health Service grants CA80163, CA73058 and CA42439 from the National Cancer Institute (to T.J.T. and T.T.), Susan G. Komen Breast Cancer Research Foundation Award (to T.T.), Alexander Von Humboldt Fellowship (to T.A.), and a Grant-in-Aid for Scientific Research from the Ministry of Education, Science and Culture, Japan (to A.S.).
PY - 2004
Y1 - 2004
N2 - We synthesized a pentamine (3-3-3-3) and two hexamine (3-3-3-3-3 and 3-4-3-4-3) analogues of the natural polyamine, spermine (3-4-3) and studied their effectiveness in condensing pGL3 plasmid DNA, using light scattering and atomic force microscopic (AFM) techniques. The midpoint concentration of the polyamines on pGL3 condensation (EC50) was 11.3, 10.6, 1.5, 0.49 and 0.52 μM, respectively, for 3-4-3, norspermine (3-3-3), 3-3-3-3, 3-3-3-3-3 and 3-4-3-4-3 in 10 mM Na cacodylate buffer. Dynamic laser light scattering study showed a decrease in hydrodynamic radii of plasmid DNA particles as the number of positive charges on the polyamines increased. AFM data showed the presence of toroids with outer diameter of 117-191 nm for different polyamines, and a mean height of 2.61 ± 0.77 nm. AFM results also revealed the presence of intermediate structures, including those showing circumferential winding of DNA to toroids. The dependence of the EC50 on Na+ concentration suggests different modes of binding of spermine and its higher valent analogues with DNA. Our results show a 20-fold increase in the efficacy of hexamines for DNA condensation compared to spermine, and provide new insights into the mechanism(s) of DNA nanoparticle formation. These studies might help to develop novel nonviral gene delivery vehicles.
AB - We synthesized a pentamine (3-3-3-3) and two hexamine (3-3-3-3-3 and 3-4-3-4-3) analogues of the natural polyamine, spermine (3-4-3) and studied their effectiveness in condensing pGL3 plasmid DNA, using light scattering and atomic force microscopic (AFM) techniques. The midpoint concentration of the polyamines on pGL3 condensation (EC50) was 11.3, 10.6, 1.5, 0.49 and 0.52 μM, respectively, for 3-4-3, norspermine (3-3-3), 3-3-3-3, 3-3-3-3-3 and 3-4-3-4-3 in 10 mM Na cacodylate buffer. Dynamic laser light scattering study showed a decrease in hydrodynamic radii of plasmid DNA particles as the number of positive charges on the polyamines increased. AFM data showed the presence of toroids with outer diameter of 117-191 nm for different polyamines, and a mean height of 2.61 ± 0.77 nm. AFM results also revealed the presence of intermediate structures, including those showing circumferential winding of DNA to toroids. The dependence of the EC50 on Na+ concentration suggests different modes of binding of spermine and its higher valent analogues with DNA. Our results show a 20-fold increase in the efficacy of hexamines for DNA condensation compared to spermine, and provide new insights into the mechanism(s) of DNA nanoparticle formation. These studies might help to develop novel nonviral gene delivery vehicles.
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U2 - 10.1093/nar/gkg936
DO - 10.1093/nar/gkg936
M3 - Article
C2 - 14704349
AN - SCOPUS:1242286990
SN - 0305-1048
VL - 32
SP - 127
EP - 134
JO - Nucleic acids research
JF - Nucleic acids research
IS - 1
ER -