Orientation and specific interactions of nucleotides and nucleolipids inside monoolein-based liquid crystals.
The entrapment of AMP, GMP, CMP, and UMP nucleotides along with two different AMP-based nucleolipids (hydrophobically functionalized nucleotides) inside the liquid crystalline phases of the monoolein/water system is investigated through optical microscopy, small-angle X-ray diffraction (SAXRD), and nuclear magnetic resonance (NMR) techniques. As ascertained mainly through (31)P NMR experiments, when included within the cubic phase, the various nucleotides undergo a slow hydrolysis of the sugar-phosphate ester bond, induced by specific interactions at the monoolein-water interface. Upon aging, the degradation of the nucleotides causes a cubic-to-hexagonal phase transition. Differently, neither hydrolysis nor alterations of the monoolein self-assembly are observed when the nucleotides are included as lipid derivatives within the cubic liquid crystalline phase. A model that explains both the hydrolysis and the consequent phase transition is presented.
Murgia
Sergio
S
Dipartimento di Scienze Chimiche, Cagliari University and CSGI, SS 554 Bivio Sestu, 09042 Monserrato (CA), Italy. murgias@unica.it
Lampis
Sandrina
S
Angius
Rossella
R
Berti
Debora
D
Monduzzi
Maura
M
D005989:Glycerides / Q000737:chemistry*; D006868:Hydrolysis; D008055:Lipids / Q000737:chemistry*; D050866:Liquid Crystals / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008956:Models, Chemical; D009711:Nucleotides / Q000737:chemistry*; D044367:Phase Transition; D053838:Scattering, Small Angle; D014961:X-Ray Diffraction
D005989:Glycerides; D008055:Lipids; D009711:Nucleotides; C005953:monoolein