Fig 1.

Structures of FK506 and FK520 (A) and genetic organization of the FK506 biosynthetic gene cluster from Streptomyces sp. KCTC 11604BP (B). The putative regulatory genes (tcs2, fkbN, and tcs7) are black. tcsA, tcsB, tcsC, and tcsD, allylmalonyl-CoA biosynthetic genes; fkbG, fkbH, fkbI, fkbJ, and fkbK, methoxymalonyl-ACP biosynthetic genes; fkbA, fkbB, and fkbC, polyketide synthase (PKS) genes; fkbL and fkbP, pipecolate biosynthesis and PKS condensation-related genes; fkbO, dihydroxycyclohexanecarboxylic acid (DHCHC) biosynthetic gene; fkbQ, type II thioestease gene; fkbD and fkbM: post-PKS genes.