Biochemical Characterization of a Novel Indole Prenyltransferase from Streptomyces sp. SN-593

• DOI: 10.1128/jb.01557-09
• Publication Date: 2010-03-27T02:25:32Z
• Authors: Shunji Takahashi; Hiroshi Takagi; Atsushi Toyoda; Masakazu Uramoto; Toshihiko Nogawa; Masashi Ueki; Yoshiyuki Sakaki; Hiroyuki Osada
• Keywords: Prenyltransferase

Genome sequencing of Streptomyces species has highlighted numerous potential genes secondary metabolite biosynthesis. The mining cryptic is important for exploring chemical diversity. Here we report the metabolite-guided genome and functional characterization a gene by biochemical studies. Based on systematic purification metabolites from sp. SN-593, isolated novel compound, 6-dimethylallylindole (DMAI)-3-carbaldehyde. Although many 6-DMAI compounds have been variety organisms, an enzyme catalyzing transfer dimethylallyl group to C-6 indole ring not reported so far. A homology search using known prenyltransferase sequences against draft sequence SN-593 revealed iptA gene. IptA protein showed 27% amino acid identity cyanobacterial LtxC, which catalyzes geranyl (-)-indolactam V. BLAST much-more-similar homologs at level than namely, SAML0654 (60%) ambofaciens ATCC 23877 SCO7467 (58%) S. coelicolor A3(2). Phylogenetic analysis that was distinct bacterial aromatic prenyltransferases fungal prenyltransferases. Detailed kinetic analyses highest catalytic efficiency (6.13 min(-1) microM(-1)) L-Trp in presence pyrophosphate (DMAPP), suggesting 6-dimethylallyl-L-Trp synthase (6-DMATS). Substrate specificity promiscuity derivatives, its reaction products were identified as compounds. Moreover, DeltaiptA mutants abolished production 6-DMAI-3-carbaldehyde well 6-dimethylallyl-L-Trp, involved 6-DMAI-3-carbaldehyde.