Characterisation of Saccharomyces cerevisiae ARO8 and ARO9 genes encoding aromatic aminotransferases I and II reveals a new aminotransferase subfamily.
The ARO8 and ARO9 genes of Saccharomyces cerevisiae were isolated by complementation of the phenylalanine/tyrosine auxotrophy of an aro8 and aro9 double-mutant strain that is defective in aromatic aminotransferase I (aro8) and II (aro9). The genes were sequenced, and deletion mutants were constructed and analysed. The expression of ARO8 and ARO9 was studied. The deduced amino acid sequences of Aro8p and Aro9p suggest that the former is a 500-residue, 56168-Da polypeptide and the latter a 513-residue, 58516-Da polypeptide. They correspond, respectively, to Ygl202p and Yhr137p, two putative proteins of unknown function revealed by systematic sequencing of the yeast genome. We show that aromatic aminotransferases I and II are homologous proteins, members of aminotransferase subgroup I, and, together with three other proteins, they constitute within the subgroup a new subfamily of enzymes specialised for aromatic amino acid and alpha-aminoadipate transamination. ARO8 expression is subject to the general control of amino acid biosynthesis. ARO9 expression is induced when aromatic amino acids are present in the growth medium and also in aro8 mutants grown on minimal ammonia medium. An autonomously replicating sequence (ARS) element is located between the ARO8 gene and YGL201c which encodes a protein of the minichromosome maintenance family.
Iraqui
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I
Laboratoire de Physiologie Cellulaire et de Génétique des Levures, Université Libre de Bruxelles, Belgium.
Vissers
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Cartiaux
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Urrestarazu
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A
D015074:2-Aminoadipic Acid / Q000378:metabolism; D000595:Amino Acid Sequence; D000596:Amino Acids / Q000378:metabolism; D000641:Ammonia / Q000378:metabolism; D001483:Base Sequence; D003001:Cloning, Molecular; D016384:Consensus Sequence; D003470:Culture Media / Q000378:metabolism; D004261:DNA Replication / Q000235:genetics; D004271:DNA, Fungal / Q000096:biosynthesis / Q000235:genetics; D004790:Enzyme Induction; D005656:Fungal Proteins / Q000235:genetics*; D017353:Gene Deletion; D015966:Gene Expression Regulation, Fungal; D005800:Genes, Fungal; D005816:Genetic Complementation Test; D007527:Isoenzymes / Q000235:genetics*; D008190:Lyases; D008969:Molecular Sequence Data; D005810:Multigene Family; D010649:Phenylalanine / Q000096:biosynthesis; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000201:enzymology / Q000235:genetics*; D016415:Sequence Alignment; D017385:Sequence Homology; D013379:Substrate Specificity; D000637:Transaminases / Q000145:classification* / Q000235:genetics*; D014443:Tyrosine / Q000096:biosynthesis; D014508:Urea / Q000378:metabolism
D000596:Amino Acids; D003470:Culture Media; D004271:DNA, Fungal; D005656:Fungal Proteins; D007527:Isoenzymes; D011993:Recombinant Fusion Proteins; D015074:2-Aminoadipic Acid; D014443:Tyrosine; D010649:Phenylalanine; D000641:Ammonia; D014508:Urea; D000637:Transaminases; C019729:aromatic amino acid aminotransferase; C427605:glutamine - phenylpyruvate transaminase; C021481:kynurenine-oxoglutarate transaminase; D008190:Lyases