The polyketide backbone was synthesized by type I polyketide synthase (PKS) and the thiazole ring was derived from a cysteine incorporated by a nonribosomal peptide synthetase (NRPS).
Type I polyketide synthase (PKS) synthesized the polyketide backbone, while a nonribosomal peptide synthetase (NRPS) added the thiazole ring through incorporation of a cysteine.