title: Evolutionary imprint of catalytic domains in fungal PKS-NRPS hybrids.
abstract: Fungal hybrid enzymes consisting of a polyketide synthase (PKS) and a nonribosomal peptide synthetase (NRPS) module are involved in the biosynthesis of a vast array of ecologically and medicinally relevant natural products. Whereas a dozen gene clusters could be assigned to the requisite PKS-NRPS pathways, the programming of the multifunctional enzymes is still enigmatic. Through engineering and heterologously expressing a chimera of PKS (lovastatin synthase, LovB) and NRPS (cytochalasin synthase, CheA) in Aspergillus terreus, we noted the potential incompatibility of a fungal highly reducing PKS (hrPKS) with the NRPS component of fungal PKS-NRPS hybrids. To rationalize the unexpected outcome of the gene fusion experiments, we conducted extensive bioinformatic analyses of fungal PKS-NRPS hybrids and LovB-type PKS. From motif studies and the function of the engineered chimeras, a noncanonical function of C-terminal condensation (C) domains in truncated PKS-NRPS homologues was inferred. More importantly, sequence alignments and phylogenetic trees revealed an evolutionary imprint of the PKS-NRPS domains, which reflect the evolutionary history of the entire megasynthase. Furthermore, a detailed investigation of C and adenylation (A) domains provides support for a scenario in which not only the A domain but also the C domain participates in amino acid selection. These findings shed new light on the complex code of this emerging class of multifunctional enzymes and will greatly facilitate future combinatorial biosynthesis and pathway engineering approaches towards natural product analogues.
authors.affiliation: Department of Biomolecular Chemistry, Leibniz Institute for Natural Product Research and Infection Biology-, Hans Knöll Institute, Beutenbergstrasse 11a, 07743 Jena, Germany.
authors.forename: Daniela
authors.initials: D
authors.lastname: Boettger
authors.forename: Holger
authors.initials: H
authors.lastname: Bergmann
authors.forename: Barbara
authors.initials: B
authors.lastname: Kuehn
authors.forename: Ekaterina
authors.initials: E
authors.lastname: Shelest
authors.forename: Christian
authors.initials: C
authors.lastname: Hertweck
mesh_terms: D000596:Amino Acids / Q000737:chemistry; D001230:Aspergillus / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D055162:Biocatalysis; D005075:Biological Evolution; D019295:Computational Biology; D026121:Indole Alkaloids / Q000737:chemistry; D008148:Lovastatin / Q000737:chemistry; D008958:Models, Molecular; D008968:Molecular Conformation; D010453:Peptide Synthases / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D010802:Phylogeny; D048630:Polyketide Synthases / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D061065:Polyketides / Q000737:chemistry; D016415:Sequence Alignment
chemical_list: D000596:Amino Acids; D026121:Indole Alkaloids; D061065:Polyketides; C019290:chaetoglobosins; D048630:Polyketide Synthases; D008148:Lovastatin; D010453:Peptide Synthases; C104385:non-ribosomal peptide synthase