title: Demonstration of an altered phenylalanyl-tRNA synthetase in an analogue-resistant mutant of Aspergillus nidulans.
abstract: We have isolated and characterized a new class of p-fluorophenylalanine (FPA)-resistant mutant in Aspergillus nidulans using a phenA strain as the wild type, by optimizing the conditions of growth. All four spontaneous mutants selected on a medium containing FPA were found to be recessive to their wild-type alleles in heterozygous diploids. Complementation analyses and linkage data showed that they were allelic and mapped at a single locus (fpaU) in the facA-riboD interval on the right arm of linkage group V. Partial purification and characterization of Phe-tRNA synthetase from wild-type and mutant strains revealed that the mutant enzyme had a greatly reduced ability to activate the analogue. It is suggested that mutation in the fpaU gene brings about a structural alteration in Phe-tRNA synthetase.
authors.affiliation: Department of Botany, Patna University, India.
authors.forename: B N
authors.initials: BN
authors.lastname: Tiwary
authors.forename: P S
authors.initials: PS
authors.lastname: Bisen
authors.forename: U
authors.initials: U
authors.lastname: Sinha
mesh_terms: D000604:Amino Acyl-tRNA Synthetases / Q000235:genetics*; D001233:Aspergillus nidulans / Q000187:drug effects / Q000201:enzymology / Q000235:genetics*; D004352:Drug Resistance, Microbial; D005796:Genes; D005800:Genes, Fungal; D005816:Genetic Complementation Test; D008040:Genetic Linkage; D005838:Genotype; D009154:Mutation; D009710:Nucleotide Mapping; D010649:Phenylalanine / Q000031:analogs & derivatives*; D010652:Phenylalanine-tRNA Ligase / Q000235:genetics*; D010135:p-Fluorophenylalanine / Q000494:pharmacology*
chemical_list: D010649:Phenylalanine; D010135:p-Fluorophenylalanine; D000604:Amino Acyl-tRNA Synthetases; D010652:Phenylalanine-tRNA Ligase