title: Low Molecular Weight Branched PEI Binding to Linear DNA.
abstract: Polyethylenimine (PEI) is one of the most versatile non-viral vectors used in gene therapy, especially for delivering plasmid DNA to human cells. However, a good understanding of PEI binding to DNA, the fundamental basis for the functioning of PEI as a vector, has been missing in the literature. In this study, PEI (branched, 600 Da) binding to DNA was examined by isothermal titration calorimetry (ITC), quartz crystal microbalance (QCM) and a complementary set of analysis tools. We demonstrated that a separation between the binding heat and the condensation heat is needed and that the excluded site model should be used for PEI binding stage in the ITC analysis. The equilibrium constant for PEI binding to DNA was determined to be 2.5×105M-1from the ITC analysis, and as 2.3×105M-1from the QCM analysis. Additionally, we suggested that the 600 Da branched PEI binds to the major groove of DNA and the rearrangement of PEI on DNA may be difficult to occur because of the small dissociation rate. The binding analysis presented here can be employed to improve our understanding of the functioning of PEI and PEI-like non-viral vectors.
authors.affiliation: Department of Science & Engineering for Materials, National Institute of Technology, Tomakomai College.
authors.forename: Kuniharu
authors.initials: K
authors.lastname: Utsuno
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Kono
authors.forename: Emika
authors.initials: E
authors.lastname: Tanaka
authors.forename: Nozomi
authors.initials: N
authors.lastname: Jouna
authors.forename: Yohichiro
authors.initials: Y
authors.lastname: Kojima
authors.forename: Hasan
authors.initials: H
authors.lastname: Uludağ
mesh_terms: D001665:Binding Sites; D002151:Calorimetry; D066241:Carbon-13 Magnetic Resonance Spectroscopy; D004247:DNA / Q000737:chemistry*; D006801:Humans; D008970:Molecular Weight; D010957:Plasmids; D011094:Polyethyleneimine / Q000737:chemistry*; D013816:Thermodynamics
chemical_list: D011094:Polyethyleneimine; D004247:DNA