 The lactone core is produced by two polyketide synthases (PKS) that are encoded by the genes, mlsA1 and mlsA2, and a third polyketide synthase, encoded by the mlsB gene, produces the fatty acid-acyl side chain.Three putative accessory genes are found in the mycolactone cluster.One of these, MUP053, encodes a p450 monooxygenase that is thought to produce the hydroxyl at C′-12 on the fatty acid side chain.