title: Evolution of the tRNA(Tyr)/TyrRS aminoacylation systems.
abstract: The tRNA identity rules ensuring fidelity of translation are globally conserved throughout evolution except for tyrosyl-tRNA synthetases (TyrRSs) that display species-specific tRNA recognition. This discrimination originates from the presence of a conserved identity pair, G1-C72, located at the top of the acceptor stem of tRNA(Tyr) from eubacteria that is invariably replaced by an unusual C1-G72 pair in archaeal and eubacterial tRNA(Tyr). In addition to the key role of pair 1-72 in tyrosylation, discriminator base A73, the anticodon triplet and the large variable region (present in eubacterial tRNA(Tyr) but not found in eukaryal tRNA(Tyr)) contribute to tyrosylation with variable strengths. Crystallographic structures of two tRNA(Tyr)/TyrRS complexes revealed different interaction modes in accordance with the phylum-specificity. Recent functional studies on the human mitochondrial tRNA(Tyr)/TyrRS system indicates strong deviations from the canonical tyrosylation rules. These differences are discussed in the light of the present knowledge on TyrRSs.
authors.affiliation: Département Mécanismes et Macromolécules de la Synthèse Protéique et Cristallogenèse, UPR 9002, Institut de Biologie Moléculaire et Cellulaire du CNRS, 15, rue René Descartes, 67084 Strasbourg cedex, France.
authors.forename: Luc
authors.initials: L
authors.lastname: Bonnefond
authors.forename: Richard
authors.initials: R
authors.lastname: Giegé
authors.forename: Joëlle
authors.initials: J
authors.lastname: Rudinger-Thirion
mesh_terms: D000412:Alanine-tRNA Ligase; D049148:Aminoacylation / Q000235:genetics*; D000926:Anticodon; D001483:Base Sequence; D017124:Conserved Sequence; D019143:Evolution, Molecular; D006801:Humans; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D011487:Protein Conformation; D012343:RNA, Transfer / Q000737:chemistry* / Q000378:metabolism; D013045:Species Specificity; D013329:Structure-Activity Relationship; D013379:Substrate Specificity; D014448:Tyrosine-tRNA Ligase / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism
chemical_list: D000926:Anticodon; D012343:RNA, Transfer; D014448:Tyrosine-tRNA Ligase; D000412:Alanine-tRNA Ligase