Lipid bilayer - DNA interaction mediated by divalent metal cations: SANS and SAXD study

Abstract

The structure of aggregates formed due to DNA interaction with dipalmitoylphosphatidylcholine (DPPC) in presence of Ca2+ and Zn 2+ is examined using small-angle synchrotron X-ray diffraction (SAXD) and small-angle neutron scattering (SANS). SAXD detected two structures: L C - condensed lamellar phase and LX - lamellar phase with DNA strands intercalated between the adjacent lipid bilayers, without regular packing at low cation concentration (∼1 mM). The high concentration of Zn2+ induces a macroscopic phase separation in mixtures. The SANS curves of DPPC+ions2+ vesicles evaluated using the strip function model have shown different modes of cations binding to the DPPC bilayers. © Published under licence by IOP Publishing Ltd.