Abstract
The structure of aggregates formed due to DNA interaction with dioleoylphosphatidylcholine (DOPC) vesicles in presence of Ca 2+ and Mg 2+ cations was investigated using synchrotron small-angle X-ray diffraction. For DOPC/DNA = 1:1 mol/base and in the range of concentration of the cation 2+ 0–76.5 mM, the diffractograms show the coexistence of two lamellar phases: L x phase with repeat distance d Lx ∼ 8.26–7.39 nm identified as a phase where the DNA strands are intercalated in water layers between adjacent lipid bilayers, and L DOPC phase with repeat distance d DOPC ∼ 6.45–5.65 nm identified as a phase of partially dehydrated DOPC bilayers without any divalent cations and DNA strands. The coexistence of these phases was investigated as a function of DOPC/DNA molar ratio, length of DNA fragments and temperature. If the amount of lipid increases, the fraction of partially dehydrated L DOPC phase is limited, depends on the portion of DNA in the sample and also on the length of DNA fragments. Thermal behaviour of DOPC + DNA + Ca 2+ aggregates was investigated in the range 20–80 °C. The transversal thermal expansivities of both phases were evaluated.
Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
