FIG. 1.

(A) Biosynthesis of Tcm F2 from malonyl-ACP and starter unit acetyl-CoA by the Tcm PKS enzymes. (Acetyl-CoA may not be the actual substrate since formation of the starter unit by decarboxylation of malonyl-ACP has been demonstrated in vitro [1, 6].) (B) Biosynthesis of AA and UWM5 from malonyl-ACP and starter unit propionyl-CoA by the daunorubicin PKS proteins. (C) Production of the 20-carbon polyketide SEK43 from malonyl-ACP and acetyl-CoA by Dps PKS enzymes without DpsC, DpsD, and DpsY.