Abstract
Model DNA-membrane contacts were studied in the system containing polyadenylic acid (polyA): polyuridilic acid (polyU) duplex and egg phosphatidylcholine (PC) vesicles without or in the presence of MgCl2. PolyU containing O-(1-oxyl-2,2,5,5-tetramethylpyrroline-3-carbonyl) spin label at 2′-OH moiety was used for spin labeling study of nucleic acid-phospholipid interactions. For polyA labeled with the same nitroxyl radical EPR spectra from spin labels attached at terminal and at internal nucleotide units contribute into the EPR spectrum of d.s. polynucleotide without or in the presence of egg PC vesicles and Mg ions. Internal spin labels are more sensitive to the interaction with PC-MLV than terminal ones. The complexation between s.s. polynucleotide and PC-MLV was shown. The values of spin labels’ melting temperature of polyA: SL-polyU duplex at 1 mM MgCl2 reflect the changes in rotational mobility of terminal spin labels connected with duplex→triplex transition. Arrhenius plots of temperature dependence of EPR spectra parameters prove that ribose moieties of sugarphosphate backbone are involved into the interaction between polynucleotide duplex and phospholipid bilayer. Egg PC vesicles demonstrate stabilizing effect on polyA: polyU duplex at 1 mM of Mg2+ and destabilizing effect at 5 mM Mg2+.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.