Title

Conformation Change Of Poly(Dg-Dc)·Poly(Dg-Dc) In Cationic Polyamine Liposome Complexes: Effect Of Charge Density And Flexibility Of Amine Chains In Headgroups

Abstract

Identification of DNA conformations in delivery cargoes is important to understand the transfection mechanisms. Conformations of poly(dG-dC)·poly(dG-dC), as a model of DNA, were studied in two different cationic liposome complexes prepared from N-[1-(2,3-dioleyloxy)propyl]-N,N,N-trimethylammonium chloride (DOT-MA) and N,NIN,II,NIII-tetramethyl-N,N I,NII,NIII-tetrapalmithyl spermine (TM-TPS) with a helper lipid, dioleoyl phosphotidylethanolamine (DOPE) by Raman microscopy. Characteristic spectral changes in guanine peaks and cytosine peaks of the poly(dG-dC)·poly(dG-dC) distinguished between the right-handed B-form and left-handed Z-form inside the cationic liposome complexes. The poly(dG-dC)·poly(dG-dC) in the TM-TPS/DOPE liposome undergoes the B-Z transition while no conformation change was observed in the poly(dG-dC)·poly(dG-dC) inside the DOTMA/DOPE liposome. Each multi-charged TM-TPS molecule contains four cationic nitrogen atoms in the headgroup. The DOTMA molecule with less cationic nitrogens does not have enough negative charges in the headgroup to cause the B-Z transition. This model was also confirmed by the B-Z transition of the poly(dG-dC)·poly(dG-dC) in another cationic polyamine liposome complex, 2,3-dioleyloxy-N-[2(sperminecarboxamido)etnyl]-N,N-dimethyl-1-propanaminium trifluoroacetate (DOSPA) and the DOPE, whose multi-charged amine chains are more flexible than the amine chains of the TM-TPS. Intermolecular interaction between cationic nitrogen atoms of the DOSPA and oxygen/nitrogen atoms of the guanine sites in poly(dG-dC)·poly(dG-dC) is considered to be one of major driving forces for the B-Z transition. Systematic studies of DNA conformations in various cationic liposome complexes may help developing improved gene delivery system. © 2000 American Chemical Society.

Publication Date

9-21-2000

Publication Title

Journal of Physical Chemistry B

Volume

104

Issue

37

Number of Pages

8871-8875

Document Type

Article

Personal Identifier

scopus

DOI Link

https://doi.org/10.1021/jp001439g

Socpus ID

0034270772 (Scopus)

Source API URL

https://api.elsevier.com/content/abstract/scopus_id/0034270772

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