Cloning and characterization of a type III polyketide synthase from Aspergillus niger

Jinglin Li, Yunzi Luo, Jung Kul Lee, Huimin Zhao

Research output: Contribution to journalArticle

Abstract

Type III polyketide synthases (PKSs) are the condensing enzymes that catalyze the formation of a myriad of aromatic polyketides in plant, bacteria, and fungi. Here we report the cloning and characterization of a putative type III PKS from Aspergillus niger, AnPKS. This enzyme catalyzes the synthesis of alkyl pyrones from C2 to C18 starter CoA thioesters with malonyl-CoA as an extender CoA through decaboxylative condensation and cyclization. It displays broad substrate specificity toward fatty acyl-CoA starters to yield triketide and tetraketide pyrones, with benzoyl-CoA as the most preferred starter. The optimal temperature and pH of AnPKS are 50 °C and 8, respectively. Under optimal conditions, the enzyme shows the highest catalytic efficiency (k cat/K m) of 7.4 × 10 5 s -1 M -1 toward benzoyl-CoA. Homology modeling and site-directed mutagenesis were used to probe the molecular basis of its substrate specificity. This study should open doors for further engineering of AnPKS as a biocatalyst for synthesis of value-added polyketides.

Original languageEnglish (US)
Pages (from-to)6085-6089
Number of pages5
JournalBioorganic and Medicinal Chemistry Letters
Volume21
Issue number20
DOIs
StatePublished - Oct 15 2011

Keywords

  • Pyrone synthase
  • Substrate specificity
  • Type III polyketide synthase

ASJC Scopus subject areas

  • Pharmaceutical Science
  • Drug Discovery
  • Organic Chemistry
  • Molecular Medicine
  • Molecular Biology
  • Clinical Biochemistry
  • Biochemistry

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