Fig. 1

a Map of pSBAC. Essential components of the vector are indicated. Ori2 and oriV, replication origins; sopA-C, partitioning system; apr ^R, apramycin resistance gene; oriT, origin of transfer; attP-int _ΦBT1, integration system; unique restriction enzyme recognition sites, EcoRI, BamHI and HindIII. b Composition of pikromycin biosynthetic gene cluster. pikAI-V, polyketide synthesis; desI-VIII, desosamine sugar synthesis; pikC, hydroxylation; pikD, regulation; pikRI-II, resistance. c Schematic description of pPik001 construction. One of HindIII recognition sites was introduced into the 150 bp upstream of pikRII and another HindIII recognition site was integrated next to pikD in pSAPDK. The pikromycin biosynthetic gene cluster was isolated by HindIII digestion of the modified chromosomal DNA and its self-ligation, then named pPik. After construction of pPik, a DNA fragment containing attP-int _ΦBT1 was inserted into the AvrII recognition site of pPik to generate pPik001