title: Maize seryl-tRNA synthetase: specificity of substrate recognition by the organellar enzyme.
abstract: In our study of seryl-tRNA formation in maize, we investigated the enzymes involved in serylation. Only two dissimilar seryl-tRNA synthetase (SerRS) cDNA clones were identified in the Zea mays EST (expressed sequence tag) databases. One encodes a seryl-tRNA synthetase, which presumably functions in the organelles (SerZMm), while the other synthetase product is more similar to eukaryotic cytosolic counterparts (SerZMc). The expression of SerZMm in Saccharomyces cerevisiae resulted in complementation of mutant respiratory phenotype, caused by a disruption of the nuclear gene, presumably encoding yeast mitochondrial seryl-tRNA synthetase (SerSCm). Purified mature SerZMm displays tRNA-assisted serine activation and aminoacylates maize mitochondrial and chloroplast tRNA(Ser) transcripts with similar efficiencies, raising the possibility that only two isoforms of seryl-tRNA synthetase may be sufficient to catalyze seryl-tRNA(Ser) formation in three cellular compartments of Zea mays. Phylogenetic analysis suggests that SerZMm is of mitochondrial origin.
authors.affiliation: Department of Chemistry, Faculty of Science, University of Zagreb, Strossmayerov trg 14, 10000 Zagreb, Croatia.
authors.forename: Jasmina
authors.initials: J
authors.lastname: Rokov-Plavec
authors.forename: Sonja
authors.initials: S
authors.lastname: Lesjak
authors.forename: Irena
authors.initials: I
authors.lastname: Landeka
authors.forename: Ivan
authors.initials: I
authors.lastname: Mijakovic
authors.forename: Ivana
authors.initials: I
authors.lastname: Weygand-Durasevic
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D002736:Chloroplasts / Q000378:metabolism; D003600:Cytosol / Q000201:enzymology; D018076:DNA, Complementary / Q000378:metabolism; D019992:Databases as Topic; D004591:Electrophoresis, Polyacrylamide Gel; D019143:Evolution, Molecular; D020224:Expressed Sequence Tags; D005816:Genetic Complementation Test; D007700:Kinetics; D008928:Mitochondria / Q000378:metabolism; D008969:Molecular Sequence Data; D009154:Mutation; D009690:Nucleic Acid Conformation; D010641:Phenotype; D010802:Phylogeny; D020033:Protein Isoforms; D012343:RNA, Transfer / Q000737:chemistry; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D012694:Serine / Q000378:metabolism; D012714:Serine-tRNA Ligase / Q000737:chemistry*; D013379:Substrate Specificity; D003313:Zea mays / Q000201:enzymology*
chemical_list: D018076:DNA, Complementary; D020033:Protein Isoforms; D012694:Serine; D012343:RNA, Transfer; D012714:Serine-tRNA Ligase