title: Conformational characteristics of the hexanucleoside pentaphosphate AUAUAU: a 2D NMR study at 500 MHz.
abstract: All 36 ribose proton resonances and most of the base proton resonances of the hexanucleoside pentaphosphate AUAUAU have been assigned unequivocally using 2D J-resolved spectroscopy, spin echo correlated spectroscopy (SECSY) and 2D NOE spectroscopy (NOESY). The NMR parameters of AUAUAU are compared with those of smaller fragments that contain methylated adenine bases: m62AU, m62AUm62A, m62AUm62AU and m62AUm62AUm62A. Previous studies on this series of compounds have shown that in all these cases purine-pyrimidine-purine sequences prefer to adopt a mixture of states which have as common feature that the interior pyrimidine residues are bulged out, whereas the purine residues stack upon each other. Chemical shift data, proton-proton coupling constants, as well as the observation of imino-proton resonances for AUAUAU show unambiguously that upon lowering the temperature the high-temperature "bulged out" situation reverts to a normal A-RNA-like double helix.
authors.forename: P P
authors.initials: PP
authors.lastname: Lankhorst
authors.forename: G A
authors.initials: GA
authors.lastname: van der Marel
authors.forename: G
authors.initials: G
authors.lastname: Wille
authors.forename: J H
authors.initials: JH
authors.lastname: van Boom
authors.forename: C
authors.initials: C
authors.lastname: Altona
mesh_terms: D003201:Computers; D009682:Magnetic Resonance Spectroscopy; D009690:Nucleic Acid Conformation; D009841:Oligonucleotides; D011522:Protons
chemical_list: D009841:Oligonucleotides; D011522:Protons