title: Fluorescence and NMR studies of intramolecular stacking of mRNA cap-analogues.
abstract: Intramolecular stacking of a series of new synthesized dinucleotide mRNA cap analogues has been investigated in aqueous buffers by means of fluorescence and 1H-NMR at various pH and temperatures, and compared with that for 7-methylguanosine(5')ppp(5')guanosine (m7GpppG), as well as its hypermethylated derivative m(3)2,2,7GpppG. Thermodynamic parameters for intramolecular self-association stabilized by stacking were established by temperature-dependent fluorescence quenching, taking into account collisional deactivation of the excited states. Relative orientations of the stacked bases in the cap analogues were determined with the aid of a program GEOSHIFT (Stolarski et al., Biochim. Biophys. Acta (1996) 1293, 97), based on ring-current anisotropy. 1D-soft-TOCSY experiments were applied to extract the exact values of vicinal coupling constants, and hence to resolve solution conformation of the cap molecules. Stacking interaction has been discussed in detail in terms of the cap structural features, e.g., types of bases and length of the 5',5'-phosphate bridges, and regarding the interactions stabilizing intramolecular stacking.
authors.affiliation: Department of Physics and Biophysics, University of Agriculture and Technology, Olsztyn, Poland.
authors.forename: Z
authors.initials: Z
authors.lastname: Wieczorek
authors.forename: K
authors.initials: K
authors.lastname: Zdanowski
authors.forename: L
authors.initials: L
authors.lastname: Chlebicka
authors.forename: J
authors.initials: J
authors.lastname: Stepiński
authors.forename: M
authors.initials: M
authors.lastname: Jankowska
authors.forename: B
authors.initials: B
authors.lastname: Kierdaszuk
authors.forename: A
authors.initials: A
authors.lastname: Temeriusz
authors.forename: E
authors.initials: E
authors.lastname: Darzynkiewicz
authors.forename: R
authors.initials: R
authors.lastname: Stolarski
mesh_terms: D006863:Hydrogen-Ion Concentration; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D009690:Nucleic Acid Conformation; D009841:Oligonucleotides / Q000737:chemistry; D012314:RNA Cap Analogs / Q000737:chemistry*; D012333:RNA, Messenger / Q000737:chemistry*; D012984:Software; D013050:Spectrometry, Fluorescence; D013696:Temperature; D013816:Thermodynamics
chemical_list: D009841:Oligonucleotides; D012314:RNA Cap Analogs; D012333:RNA, Messenger