title: Engineering of the spinosyn PKS: directing starter unit incorporation.
abstract: The spinosyns are a family of potent and highly selective insect control agents that display a favorable environmental profile. As some regions of the spinosyn molecule are recalcitrant to chemical modification, a targeted genetic approach was carried out to generate new analogues. The polyketide synthase (PKS) loading modules from the avermectin PKS of Streptomyces avermitilis and the erythromcyin PKS of Saccharopolyspora erythraea were each used to replace the spinosyn PKS loading module. Both of the resulting strains containing hybrid PKS pathways produced the anticipated spinosyn analogues. Supplementation of the culture media with a range of exogenous carboxylic acids led to the successful incorporation of these novel elements to yield further novel spinosyn molecules, some of which demonstrated potent and new insecticidal activities. Furthermore, it has been demonstrated that semisynthesis of such novel metabolites can then be used to generate active analogues, demonstrating the effectiveness of utilizing these complementary methods to search the chemical space around this template.
authors.affiliation: Biotica Technology Limited, Chesterford Research Park, Essex, CB10 1XL, U.K.
authors.forename: Lesley S
authors.initials: LS
authors.lastname: Sheehan
authors.forename: Rachel E
authors.initials: RE
authors.lastname: Lill
authors.forename: Barrie
authors.initials: B
authors.lastname: Wilkinson
authors.forename: Rose M
authors.initials: RM
authors.lastname: Sheridan
authors.forename: William A
authors.initials: WA
authors.lastname: Vousden
authors.forename: Andrew L
authors.initials: AL
authors.lastname: Kaja
authors.forename: Gary D
authors.initials: GD
authors.lastname: Crouse
authors.forename: James
authors.initials: J
authors.lastname: Gifford
authors.forename: Paul R
authors.initials: PR
authors.lastname: Graupner
authors.forename: Laura
authors.initials: L
authors.lastname: Karr
authors.forename: Paul
authors.initials: P
authors.lastname: Lewer
authors.forename: Thomas C
authors.initials: TC
authors.lastname: Sparks
authors.forename: Peter F
authors.initials: PF
authors.lastname: Leadlay
authors.forename: Clive
authors.initials: C
authors.lastname: Waldron
authors.forename: Christine J
authors.initials: CJ
authors.lastname: Martin
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D004247:DNA / Q000737:chemistry*; D004917:Erythromycin / Q000737:chemistry; D004926:Escherichia coli / Q000378:metabolism; D007306:Insecticides / Q000737:chemistry*; D007559:Ivermectin / Q000031:analogs & derivatives / Q000737:chemistry; D018942:Macrolides / Q000737:chemistry*; D008958:Models, Molecular; D048630:Polyketide Synthases / Q000737:chemistry*; D015202:Protein Engineering; D016930:Saccharopolyspora / Q000201:enzymology / Q000378:metabolism; D013302:Streptomyces / Q000201:enzymology / Q000378:metabolism; D040102:Tetranychidae / Q000187:drug effects*
chemical_list: D007306:Insecticides; D018942:Macrolides; D004917:Erythromycin; D007559:Ivermectin; C019264:avermectin; D048630:Polyketide Synthases; D004247:DNA