title: Glutamine-330 is not essential for activity in isopenicillin N synthase from Aspergillus nidulans.
abstract: The non-heme ferrous dependent oxidase isopenicillin N synthase (IPNS) catalyses the biosynthesis of isopenicillin N from a tripeptide substrate. The crystal structure of Aspergillus nidulans IPNS complexed to manganese reveals a six co-ordinate metal ligated by two water molecules and four protein ligands: His-214, His-270, Asp-216 and Gln-330 (the penultimate C-terminal residue). Modification of Gln-330 to Ala or Leu, or deletion of 2 or 6 residues from the C-terminus resulted in lowering of specific activity; no activity was observed after deletion of 8 residues. The results demonstrate that metal ligation by Gln-330 is not required for catalytic activity.
authors.affiliation: Dyson Perrins Laboratory and the Oxford Center for Molecular Sciences, UK.
authors.forename: M
authors.initials: M
authors.lastname: Sami
authors.forename: T J
authors.initials: TJ
authors.lastname: Brown
authors.forename: P L
authors.initials: PL
authors.lastname: Roach
authors.forename: C J
authors.initials: CJ
authors.lastname: Schofield
authors.forename: J E
authors.initials: JE
authors.lastname: Baldwin
mesh_terms: D000595:Amino Acid Sequence; D001233:Aspergillus nidulans / Q000201:enzymology* / Q000235:genetics; D001665:Binding Sites; D005973:Glutamine / Q000235:genetics; D007700:Kinetics; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009154:Mutation; D010088:Oxidoreductases / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D013329:Structure-Activity Relationship; D013912:Threonine / Q000235:genetics
chemical_list: D011994:Recombinant Proteins; D005973:Glutamine; D013912:Threonine; D010088:Oxidoreductases; C038370:isopenicillin N synthetase