title: tRNA-like recognition of group I introns by a tyrosyl-tRNA synthetase.
abstract: The Neurospora crassa mitochondrial tyrosyl-tRNA synthetase (CYT-18 protein) functions in splicing group I introns by promoting the formation of the catalytically active RNA structure. Previous work suggested that CYT-18 recognizes a conserved tRNA-like structure of the group I intron catalytic core. Here, directed hydroxyl-radical cleavage assays show that the nucleotide-binding fold and C-terminal domains of CYT-18 interact with the expected group I intron cognates of the aminoacyl-acceptor stem and D-anticodon arms, respectively. Further, three-dimensional graphic modeling, supported by biochemical data, shows that conserved regions of group I introns can be superimposed over interacting regions of the tRNA in a Thermus thermophilus TyrRS/tRNA(Tyr) cocrystal structure. Our results support the hypothesis that CYT-18 and other aminoacyl-tRNA synthetases interact with group I introns by recognizing conserved tRNA-like structural features of the intron RNAs.
authors.affiliation: Institute for Cellular and Molecular Biology, Department of Chemistry and Biochemistry, and Section of Molecular Genetics and Microbiology, School of Biological Sciences, University of Texas, Austin, TX 78712, USA.
authors.forename: Christopher A
authors.initials: CA
authors.lastname: Myers
authors.forename: Birte
authors.initials: B
authors.lastname: Kuhla
authors.forename: Stephen
authors.initials: S
authors.lastname: Cusack
authors.forename: Alan M
authors.initials: AM
authors.lastname: Lambowitz
mesh_terms: D003001:Cloning, Molecular; D003545:Cysteine; D017665:Hydroxyl Radical; D007438:Introns; D008958:Models, Molecular; D009492:Neurospora crassa / Q000201:enzymology / Q000235:genetics; D009690:Nucleic Acid Conformation; D020836:Protein Structure, Quaternary; D012343:RNA, Transfer / Q000737:chemistry / Q000378:metabolism*; D014448:Tyrosine-tRNA Ligase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
chemical_list: D017665:Hydroxyl Radical; D012343:RNA, Transfer; D014448:Tyrosine-tRNA Ligase; D003545:Cysteine