title: A tyrosyl-tRNA synthetase recognizes a conserved tRNA-like structural motif in the group I intron catalytic core.
abstract: The Neurospora crassa mitochondrial (mt) tyrosyl-tRNA synthetase (CYT-18 protein) functions in splicing group I introns, in addition to aminoacylating tRNA(Tyr). Here, we compared the CYT-18 binding sites in the N. crassa mt LSU and ND1 introns with that in N. crassa mt tRNA(Tyr) by constructing three-dimensional models based on chemical modification and RNA footprinting data. Remarkably, superimposition of the CYT-18 binding sites in the model structures revealed an extended three-dimensional overlap between the tRNA and the group I intron catalytic core. Our results provide insight into how an RNA-splicing factor can evolve from a cellular RNA-binding protein. Further, the structural similarities between group I introns and tRNAs are consistent with an evolutionary relationship and suggest a general mechanism for the evolution of complex catalytic RNAs.
authors.affiliation: Department of Molecular Genetics, The Ohio State University, Columbus 43210-1292, USA.
authors.forename: M G
authors.initials: MG
authors.lastname: Caprara
authors.forename: V
authors.initials: V
authors.lastname: Lehnert
authors.forename: A M
authors.initials: AM
authors.lastname: Lambowitz
authors.forename: E
authors.initials: E
authors.lastname: Westhof
mesh_terms: D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D005075:Biological Evolution; D017124:Conserved Sequence; D007438:Introns; D008969:Molecular Sequence Data; D009492:Neurospora crassa; D009690:Nucleic Acid Conformation; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D012326:RNA Splicing / Q000502:physiology; D012331:RNA, Fungal / Q000737:chemistry / Q000378:metabolism / Q000502:physiology; D012365:RNA, Transfer, Tyr / Q000737:chemistry; D014448:Tyrosine-tRNA Ligase / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism
chemical_list: D012331:RNA, Fungal; D012365:RNA, Transfer, Tyr; D014448:Tyrosine-tRNA Ligase