TY - JOUR
T1 - Cloning and characterization of a type III polyketide synthase from Aspergillus niger
AU - Li, Jinglin
AU - Luo, Yunzi
AU - Lee, Jung Kul
AU - Zhao, Huimin
N1 - Funding Information:
This work was supported by the National Research Foundation of Korea (NRF) Grant funded by the Korea government (MEST) (220-2009-1-D00033).
PY - 2011/10/15
Y1 - 2011/10/15
N2 - 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.
AB - 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.
KW - Pyrone synthase
KW - Substrate specificity
KW - Type III polyketide synthase
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U2 - 10.1016/j.bmcl.2011.08.058
DO - 10.1016/j.bmcl.2011.08.058
M3 - Article
C2 - 21903388
AN - SCOPUS:80052960391
VL - 21
SP - 6085
EP - 6089
JO - Bioorganic and Medicinal Chemistry Letters
JF - Bioorganic and Medicinal Chemistry Letters
SN - 0960-894X
IS - 20
ER -