title: Yeast N-terminal amidase. A new enzyme and component of the N-end rule pathway.
abstract: The N-end rule relates the in vivo half-life of a protein to the identity of its N-terminal residue. Tertiary destabilizing N-terminal residues asparagine and glutamine function through their conversion, by enzymatic deamidation, into the secondary destabilizing residues aspartate and glutamate, whose activity requires their enzymatic conjugation to arginine, one of the primary destabilizing residues. We isolated a Saccharomyces cerevisiae gene, termed NTA1, that encodes an amidase (Nt-amidase) specific for N-terminal asparagine and glutamine. Alterations at the putative active-site cysteine of the 52-kDa Nt-amidase inactivate the enzyme. Null nta1 mutants are viable but unable to degrade N-end rule substrates that bear N-terminal asparagine or glutamine. The effects of overexpressing Nt-amidase and other components of the N-end rule pathway suggest interactions between these components and the existence of a multienzyme targeting complex.
authors.affiliation: Division of Biology, California Institute of Technology, Pasadena 91125, USA.
authors.forename: R T
authors.initials: RT
authors.lastname: Baker
authors.forename: A
authors.initials: A
authors.lastname: Varshavsky
mesh_terms: D000217:Acyltransferases / Q000378:metabolism; D000581:Amidohydrolases / Q000235:genetics / Q000302:isolation & purification*; D000595:Amino Acid Sequence; D000596:Amino Acids / Q000737:chemistry; D019881:Aminoacyltransferases; D001216:Asparagine / Q000378:metabolism; D001224:Aspartic Acid / Q000378:metabolism; D001483:Base Sequence; D002240:Carbohydrate Sequence; D003001:Cloning, Molecular; D003062:Codon; D005656:Fungal Proteins / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D005800:Genes, Fungal; D018698:Glutamic Acid / Q000378:metabolism; D005973:Glutamine / Q000378:metabolism; D006207:Half-Life; D008025:Ligases; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009097:Multienzyme Complexes / Q000378:metabolism; D011401:Promoter Regions, Genetic; D011499:Protein Processing, Post-Translational; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000201:enzymology* / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000302:isolation & purification*; D044767:Ubiquitin-Protein Ligases
chemical_list: D000596:Amino Acids; D003062:Codon; D005656:Fungal Proteins; D009097:Multienzyme Complexes; D011993:Recombinant Fusion Proteins; D029701:Saccharomyces cerevisiae Proteins; D005973:Glutamine; D001224:Aspartic Acid; D018698:Glutamic Acid; D001216:Asparagine; D000217:Acyltransferases; D019881:Aminoacyltransferases; C066066:UBR1 protein, S cerevisiae; D044767:Ubiquitin-Protein Ligases; C019727:arginyltransferase; D000581:Amidohydrolases; C585586:NTA1 protein, S cerevisiae; C019665:amidase; D008025:Ligases