title: Binding interactions between yeast tRNA ligase and a precursor transfer ribonucleic acid containing two photoreactive uridine analogues.
abstract: Yeast tRNA ligase, from Saccharomyces cerevisiae, is one of the protein components that is involved in the splicing reaction of intron-containing yeast precursor tRNAs. It is an unusual protein because it has three distinct catalytic activities. It functions as a polynucleotide kinase, as a cyclic phosphodiesterase, and as an RNA ligase. We have studied the binding interactions between ligase and precursor tRNAs containing two photoreactive uridine analogues, 4-thiouridine and 5-bromouridine. When irradiated with long ultraviolet light, RNA containing these analogues can form specific covalent bonds with associated proteins. In this paper, we show that 4-thiouridine triphosphate and 5-bromouridine triphosphate were readily incorporated into a precursor tRNA(Phe) that was synthesized, in vitro, with bacteriophage T7 RNA polymerase. The analogue-containing precursor tRNAs were authentic substrates for the two splicing enzymes that were tested (endonuclease and ligase), and they formed specific covalent bonds with ligase when they were irradiated with long-wavelength ultraviolet light. We have determined the position of three major cross-links and one minor cross-link on precursor tRNA(Phe) that were located within the intron and near the 3' splice site. On the basis of these data, we present a model for the in vivo splicing reaction of yeast precursor tRNAs.
authors.affiliation: Department of Biology, California Institute of Technology, Pasadena 91125.
authors.forename: N K
authors.initials: NK
authors.lastname: Tanner
authors.forename: M M
authors.initials: MM
authors.lastname: Hanna
authors.forename: J
authors.initials: J
authors.lastname: Abelson
mesh_terms: D001483:Base Sequence; D003432:Cross-Linking Reagents; D007202:Indicators and Reagents; D007700:Kinetics; D008957:Models, Genetic; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D010727:Phosphoric Diester Hydrolases / Q000378:metabolism*; D010770:Phosphotransferases / Q000378:metabolism*; D011116:Polynucleotide 5'-Hydroxyl-Kinase / Q000378:metabolism*; D011118:Polynucleotide Ligases / Q000378:metabolism*; D012322:RNA Precursors / Q000235:genetics / Q000378:metabolism* / Q000528:radiation effects; D012326:RNA Splicing; D012360:RNA, Transfer, Phe / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000201:enzymology* / Q000235:genetics; D014500:Uracil Nucleotides / Q000031:analogs & derivatives*; D014544:Uridine Triphosphate / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000378:metabolism
chemical_list: D003432:Cross-Linking Reagents; D007202:Indicators and Reagents; D012322:RNA Precursors; D012360:RNA, Transfer, Phe; D014500:Uracil Nucleotides; C059150:tRNA ligase, yeast; C059149:4-thiouridine triphosphate; C018009:5-bromouridine triphosphate; D010770:Phosphotransferases; D011116:Polynucleotide 5'-Hydroxyl-Kinase; D010727:Phosphoric Diester Hydrolases; D011118:Polynucleotide Ligases; D014544:Uridine Triphosphate