TY - JOUR
T1 - Molecular restructuring of water and lipids upon the interaction of DNA with lipid monolayers
AU - Campen, R. Kramer
AU - Ngo, Thuy T.M.
AU - Sovago, Maria
AU - Ruysschaert, Jean Marie
AU - Bonn, Mischa
PY - 2010/6/16
Y1 - 2010/6/16
N2 - Understanding the molecular mechanism of DNA/lipid interaction is critical in optimizing the use of lipid cofactors in gene therapy. Here, we address this question by employing label-free vibrational sum frequency (VSF) spectroscopy to study the interaction of DNA with lipid monolayers of the cationic lipids DPTAP(1,2-dipalmitoyl-3-trimethylammonium-propane) and diC14-amidine as well as the zwitterionic lipid DPPC (1,2-dipalmitoyl-sn-glycero-3-phosphocholine) in the presence and absence of calcium. Our approach has the advantage both of allowing us to explicitly probe intermolecular interactions and of providing insight into the structure of water and lipids around DNA at the lipid interface. We find, by examination of the OD stretch of interfacial D 2O, that water structure differs markedly between systems containing DNA adsorbed to cationic and those that contain DNA adsorbed to zwitterionic lipid monolayers (in the presence or absence of Ca2+). The spectral response of interfacial water in the cationic system is consistent with a highly structured, undercoordinated, structural type of water. Further, by investigation of CH stretch modes of the diC14-amidine lipid tails, we demonstrate that the adsorption of DNA to this lipid leads to increased ordering of lipid tails.
AB - Understanding the molecular mechanism of DNA/lipid interaction is critical in optimizing the use of lipid cofactors in gene therapy. Here, we address this question by employing label-free vibrational sum frequency (VSF) spectroscopy to study the interaction of DNA with lipid monolayers of the cationic lipids DPTAP(1,2-dipalmitoyl-3-trimethylammonium-propane) and diC14-amidine as well as the zwitterionic lipid DPPC (1,2-dipalmitoyl-sn-glycero-3-phosphocholine) in the presence and absence of calcium. Our approach has the advantage both of allowing us to explicitly probe intermolecular interactions and of providing insight into the structure of water and lipids around DNA at the lipid interface. We find, by examination of the OD stretch of interfacial D 2O, that water structure differs markedly between systems containing DNA adsorbed to cationic and those that contain DNA adsorbed to zwitterionic lipid monolayers (in the presence or absence of Ca2+). The spectral response of interfacial water in the cationic system is consistent with a highly structured, undercoordinated, structural type of water. Further, by investigation of CH stretch modes of the diC14-amidine lipid tails, we demonstrate that the adsorption of DNA to this lipid leads to increased ordering of lipid tails.
UR - http://www.scopus.com/inward/record.url?scp=77953314650&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=77953314650&partnerID=8YFLogxK
U2 - 10.1021/ja100838q
DO - 10.1021/ja100838q
M3 - Article
C2 - 20486664
AN - SCOPUS:77953314650
SN - 0002-7863
VL - 132
SP - 8037
EP - 8047
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
IS - 23
ER -