FIG. 1.

Effects of rppA and P-450mel on melanin production by S. griseus. (A) Gene organization of the S. griseus chromosomal region including the rppA and P-450mel loci and the DNA fragments on the plasmids used in this study. The ΔP-450mel mutant contains an in-frame deletion from Glu-84 to Tyr-250. OrfA is similar to transcriptional factors of the AraC family. The orfBCDE operon constitutes an ABC transporter, because of the similarity of OrfB to substrate-binding extracellular domains, OrfCD to membrane integral subunits, and OrfE to ATP-binding proteins. OrfF and OrfG are similar to subtilisin-type serine proteases and chitinases, respectively. (B) Phenotypes of ΔP-450mel and ΔrppA mutants. The strains were grown at 28°C for 3 days on R5 medium.