title: Base pairing within the psi32,psi39-modified anticodon arm of Escherichia coli tRNA(Phe).
abstract: The base-base hydrogen bond interactions of the psi32,psi39-modified anticodon arm of Escherichia coli tRNAPhe have been investigated using heteronuclear NMR spectroscopy. psi32 and psi39 were enzymatically introduced into a [13C,15N]-isotopically enriched RNA sequence corresponding to the tRNAPhe anticodon arm. Both the psi32-A38 and A31-psi39 nucleotide pairs form Watson-Crick base pairing schemes and the anticodon nucleotides adopt a triloop conformation. Similar effects were observed previously with D2-isopentenyl modification of the A37 N6 that also is native to the tRNAPhe anticodon arm. These results demonstrate that the individual modifications are not sufficient to produce the 32-38 bifurcated hydrogen bond or the U-turn motifs that are observed in crystal structures of tRNAs and tRNA-protein complexes. Thus the formation of these conserved structural features in solution likely require the synergistic interaction of multiple modifications.
authors.affiliation: Department of Biochemistry and Cell Biology, Rice University, Houston, Texas 77251, USA.
authors.forename: Izabela
authors.initials: I
authors.lastname: Tworowska
authors.forename: Edward P
authors.initials: EP
authors.lastname: Nikonowicz
mesh_terms: D000926:Anticodon / Q000737:chemistry* / Q000235:genetics; D020029:Base Pairing; D001483:Base Sequence; D004926:Escherichia coli / Q000235:genetics*; D006860:Hydrogen Bonding; D019751:Intramolecular Transferases / Q000235:genetics / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy; D009690:Nucleic Acid Conformation; D011560:Pseudouridine / Q000235:genetics / Q000378:metabolism*; D012360:RNA, Transfer, Phe / Q000737:chemistry* / Q000235:genetics; D012270:Ribosomes / Q000235:genetics
chemical_list: D000926:Anticodon; D012360:RNA, Transfer, Phe; D011560:Pseudouridine; D019751:Intramolecular Transferases; C096995:pseudouridine synthases