The structural variety of DNA-DPPC-divalent metal cation aggregates: SAXD and SANS study

• Published in: The European physical journal. ST, Special topics Vol. 167; no. 1; pp. 191 - 197
• Main Authors: Uhríková, D., Pullmannová, P., Kučerka, N., Funari, S. S., Teixeira, J., Balgavý, P.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Berlin/Heidelberg Springer-Verlag 01.02.2009; EDP Sciences
• Subjects: Atomic; Classical and Continuum Physics; Condensed Matter Physics; Condensed matter: structure, mechanical and thermal properties; Exact sciences and technology; Liquid crystals; Materials Science; Measurement Science and Instrumentation; Molecular; Optical and Plasma Physics; Physics; Physics and Astronomy; Regular Article; Salmonidae; Structure of solids and liquids; crystallography; Repeat Distance; DPPC Bilayer; Lateral Segregation; European Physical Journal Special Topic; DPPC; Vesicles; Small angle neutron scattering; Segregation; DNA; Inhomogeneity; XRD; Liquid crystals; Dissolution; Phase transitions; Neutron diffusion; Synchrotron radiation
• ISSN: 1951-6355; 1951-6401
• DOI: 10.1140/epjst/e2009-00957-0

We examine the structure of aggregates formed due to DNA interaction with dipalmitoylphosphatidylcholine (DPPC) in presence of Ca 2+ and Zn 2+ using small-angle synchrotron X-ray diffraction (SAXD) and neutron scattering (SANS). SAXD shows structural heterogeneity as a function of the cation concentration and temperature: At low cation concentration (∼1 mM), aggregates show two DPPC phases, one with a lateral segregation of DNA and cation, while higher cation concentration improves the DNA packing and the condensed lamellar phase is observed in DNA+DPPC+20mMion 2+ aggregates. The SANS detected the dissolution of the condensed lamellar phase into unilamellar DPPC+Zn 2+ vesicles due to gel ↦ liquid-crystal phase transition in DNA+DPPC+20mM Zn 2+ aggregates with the short fragmented salmon sperm DNA.