FIG. 5.

Inactivation of valA of the validamycin biosynthetic gene cluster. (A) Schematic representation of the replacement of a 563-bp internal fragment of valA with the 1.4-kb aac(3)IV. In shuttle plasmid pJTU519, aac(3)IV was inserted between 1.3-kb and 1.5-kb genomic fragments originally flanking the deleted 563-bp region. While wild-type 5008 should give a 1.2-kb PCR-amplified product, mutant JXH-1 should yield a 2.1-kb product using a pair of primers (ValA-F and ValA-R) designed for amplification of full-length valA. (B) PCR analysis of wild-type 5008 and mutant JXH-1. (C) HPLC comparison between 5008 and JXH-1. The peak corresponding to validamycin A is absent from mutant JXH-1.