title: Functional expression of the Aspergillus flavus PKS-NRPS hybrid CpaA involved in the biosynthesis of cyclopiazonic acid.
abstract: alpha-Cyclopiazonic acid (CPA) is an indole tetramic acid mycotoxin. Based on our identification of the polyketide synthase-nonribosomal peptide synthase (PKS-NRPS) hybrid gene cpaA involved in cyclopiazonic acid biosynthesis in Aspergillus fungi, we carried out heterologous expression of Aspergillus flavuscpaA under alpha-amylase promoter in Aspergillus oryzae and identified its sole product to be the CPA biosynthetic intermediate cyclo-acetoacetyl-l-tryptophan (cAATrp). This result rationalized that the PKS-NRPS hybrid enzyme CpaA catalyzes condensation of the diketide acetoacetyl-ACP formed by the PKS module and l-Trp activated by the NRPS module. This CpaA expression system provides us an ideal platform for PKS-NRPS functional analysis, such as adenylation domain selectivity and product releasing mechanism.
authors.affiliation: School of Pharmacy, Iwate Medical University, 2-1-1 Nishitokuta, Yahaba, Iwate 028-3694, Japan.
authors.forename: Yasuyo
authors.initials: Y
authors.lastname: Seshime
authors.forename: Praveen Rao
authors.initials: PR
authors.lastname: Juvvadi
authors.forename: Masafumi
authors.initials: M
authors.lastname: Tokuoka
authors.forename: Yasuji
authors.initials: Y
authors.lastname: Koyama
authors.forename: Katsuhiko
authors.initials: K
authors.lastname: Kitamoto
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Ebizuka
authors.forename: Isao
authors.initials: I
authors.lastname: Fujii
mesh_terms: D001231:Aspergillus flavus / Q000201:enzymology*; D007211:Indoles / Q000138:chemical synthesis* / Q000378:metabolism; D053858:Metabolic Networks and Pathways; D009183:Mycotoxins; D010453:Peptide Synthases / Q000737:chemistry / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D000516:alpha-Amylases / Q000235:genetics
chemical_list: D007211:Indoles; D009183:Mycotoxins; D000516:alpha-Amylases; D010453:Peptide Synthases; C104385:non-ribosomal peptide synthase; C000543:cyclopiazonic acid