title: Thiobacillus ferrooxidans tyrosyl-tRNA synthetase functions in vivo in Escherichia coli.
abstract: The tyrosyl-tRNA synthetase gene (tyrZ) from Thiobacillus ferrooxidans, an acidophilic, autotrophic, gram-negative bacterium that participates in bioleaching of minerals, was cloned and sequenced. The encoded polypeptide (TyrRZ) is 407 amino acids in length (molecular mass; 38 kDa). The predicted protein sequence has an extensive overall identity (44%) to the sequence of the protein encoded by the Bacillus subtilus tyrZ gene, one of the two genes encoding tyrosyl-tRNA synthetases in this microorganism. Alignment with Escherichia coli TyrRS revealed limited overall identity (24%), except in the regions of the signature sequence for class I aminoacyl-tRNA synthetases. Complementation of an E. coli strain with a thermosensitive mutation in TyrRS showed that the protein encoded by the T. ferrooxidans tyrZ gene is functional and recognizes the E. coli tRNA(Tyr) as a substrate. TyrZ is a single-copy gene as revealed by Southern blot analysis. The gene was localized upstream from the putative promoters of the rrnT2 ribosomal RNA operon. Although no rho-independent transcription terminator was found between the two genes, a 1.3-kb RNA hybridized to a DNA probe derived from the tyrZ gene. The functional relationship between these two transcription units is discussed.
authors.affiliation: Departamento de Bioquímica, Facultad de Medicina, Universidad de Chile, Santiago.
authors.forename: O
authors.initials: O
authors.lastname: Salazar
authors.forename: B
authors.initials: B
authors.lastname: Sagredo
authors.forename: E
authors.initials: E
authors.lastname: Jedlicki
authors.forename: D
authors.initials: D
authors.lastname: Söll
authors.forename: I
authors.initials: I
authors.lastname: Weygand-Durasevic
authors.forename: O
authors.initials: O
authors.lastname: Orellana
mesh_terms: D013856:Acidithiobacillus thiooxidans / Q000201:enzymology* / Q000235:genetics; D000595:Amino Acid Sequence; D001483:Base Sequence; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D005816:Genetic Complementation Test; D008969:Molecular Sequence Data; D009154:Mutation; D009693:Nucleic Acid Hybridization; D009876:Operon; D011401:Promoter Regions, Genetic; D012329:RNA, Bacterial / Q000378:metabolism; D012335:RNA, Ribosomal / Q000235:genetics; D012365:RNA, Transfer, Tyr / Q000378:metabolism; D017422:Sequence Analysis, DNA; D014448:Tyrosine-tRNA Ligase / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism
chemical_list: D012329:RNA, Bacterial; D012335:RNA, Ribosomal; D012365:RNA, Transfer, Tyr; D014448:Tyrosine-tRNA Ligase