Eta A. Isiorho

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Spinosyns A and D (spinosad) are complex polyketide natural products biosynthesized through the cooperation of a modular polyketide synthase and several tailoring enzymes. SpnP catalyzes the final tailoring step, transferring forosamine from a TDP-D-forosamine donor substrate to a spinosyn pseudoaglycone acceptor substrate. Sequence analysis indicated that(More)
In the biosynthetic pathway of the spinosyn insecticides, the tailoring enzyme SpnF performs a [4 + 2] cycloaddition on a 22-membered macrolactone to forge an embedded cyclohexene ring. To learn more about this reaction, which could potentially proceed through a Diels-Alder mechanism, we determined the 1.50-Å-resolution crystal structure of SpnF bound to(More)
Spinosyn A is a polyketide-derived macrolide produced by Saccharopolyspora spinosa and is an active ingredient in several commercial insecticides. It is glycosylated by a tri-O-methylated rhamnose at C-9 and a forosamine at C-17. Previous studies indicated that the rhamnose methyltransferases are encoded by the spnH, spnI, and spnK genes. To verify the(More)
Spinosyns A and D (spinosad), like many other complex polyketides, are tailored near the end of their biosyntheses through the addition of sugars. SpnG, which catalyzes their 9-OH rhamnosylation, is also capable of adding other monosaccharides to the spinosyn aglycone (AGL) from TDP-sugars; however, the substitution of UDP-D-glucose for TDP-D-glucose as the(More)
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