title: Identification in archaea of a novel D-Tyr-tRNATyr deacylase.
abstract: Most bacteria and eukarya contain an enzyme capable of specifically hydrolyzing D-aminoacyl-tRNA. Here, the archaea Sulfolobus solfataricus is shown to also contain an enzyme activity capable of recycling misaminoacylated D-Tyr-tRNATyr. N-terminal sequencing of this enzyme identifies open reading frame SS02234 (dtd2), the product of which does not present any sequence homology with the known D-Tyr-tRNATyr deacylases of bacteria or eukaryotes. On the other hand, homologs of dtd2 occur in archaea and plants. The Pyrococcus abyssi dtd2 ortholog (PAB2349) was isolated. It rescues the sensitivity to D-tyrosine of a mutant Escherichia coli strain lacking dtd, the gene of its endogeneous D-Tyr-tRNATyr deacylase. Moreover, in vitro, the PAB2349 product, which behaves as a monomer and carries 2 mol of zinc/mol of protein, catalyzes the cleavage of D-Tyr-tRNATyr. The three-dimensional structure of the product of the Archaeoglobus fulgidus dtd2 ortholog has been recently solved by others through a structural genomics approach (Protein Data Bank code 1YQE). This structure does not resemble that of Escherichia coli D-Tyr-tRNATyr deacylase. Instead, it displays homology with that of a bacterial peptidyl-tRNA hydrolase. We show, however, that the archaeal PAB2349 enzyme does not act against diacetyl-Lys-tRNALys, a model substrate of peptidyl-tRNA hydrolase. Based on the Protein Data Bank 1YQE structure, site-directed mutagenesis experiments were undertaken to remove zinc from the PAB2349 enzyme. Several residues involved in zinc binding and supporting the activity of the deacylase were identified. Taken together, these observations suggest evolutionary links between the various hydrolases in charge of the recycling of metabolically inactive tRNAs during translation.
authors.affiliation: Laboratoire de Biochimie, UMR CNRS 7654, Département de Biologie, Ecole Polytechnique, 91128 Palaiseau Cedex, France.
authors.forename: Maria-Laura
authors.initials: ML
authors.lastname: Ferri-Fioni
authors.forename: Michel
authors.initials: M
authors.lastname: Fromant
authors.forename: Anne-Pascale
authors.initials: AP
authors.lastname: Bouin
authors.forename: Caroline
authors.initials: C
authors.lastname: Aubard
authors.forename: Christine
authors.initials: C
authors.lastname: Lazennec
authors.forename: Pierre
authors.initials: P
authors.lastname: Plateau
authors.forename: Sylvain
authors.initials: S
authors.lastname: Blanquet
mesh_terms: D000595:Amino Acid Sequence; D019881:Aminoacyltransferases / Q000737:chemistry*; D001105:Archaea / Q000378:metabolism*; D019611:Archaeoglobus fulgidus / Q000378:metabolism; D002384:Catalysis; D004926:Escherichia coli / Q000378:metabolism; D007477:Ions; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009154:Mutation; D043903:Pyrococcus abyssi / Q000378:metabolism; D012365:RNA, Transfer, Tyr / Q000737:chemistry*; D017386:Sequence Homology, Amino Acid; D048229:Sulfolobus solfataricus / Q000378:metabolism; D015032:Zinc / Q000737:chemistry
chemical_list: D007477:Ions; D012365:RNA, Transfer, Tyr; D019881:Aminoacyltransferases; C120167:D-tyrosine tRNA(Tyr) deacylase; D015032:Zinc