Genetic organization of the biosynthetic gene cluster for the indolocarbazole K-252a in Nonomuraea longicatena JCM 11136.
Indolocarbazole metabolite K-252a is a natural product that was previously reported as a potent protein kinase C inhibitor with in vitro and in vivo potency. From a biosynthetic viewpoint, this compound possesses structurally interesting features such as an unusual furanosyl sugar moiety, which are absent in the well-studied staurosporine and rebeccamycin. A cosmid library from genomic DNA of Nonomuraea longicatena JCM 11136 was constructed and screened for the presence of genes to be involved in the biosynthesis of indolocarbazole K-252a. Using as a probe an internal fragment of vioB, a Chromobacterium violaceum gene encoding a multifunctional enzyme that catalyzes tryptophan decarboxylation and condensation reaction in violacein biosynthesis, we isolated a DNA region that directed the biosynthesis of K-252a when introduced into the heterologous expression host Streptomyces albus. Sequence analysis of 45 kb revealed genes for indolocarbazole core formation, glycosylation, and sugar methylation, as well as a regulatory gene and two resistance/secretion genes. The cloned genes should help to elucidate the molecular basis for indolocarbazole biosynthesis and generate new indolocarbazole analogues by genetic engineering.
Kim
Seung-Young
SY
Department of Agricultural Biotechnology, Seoul National University, Seoul, 151-921, South Korea.
Park
Jin-Soo
JS
Chae
Choong-Sik
CS
Hyun
Chang-Gu
CG
Choi
Byoung Wook
BW
Shin
Jongheon
J
Oh
Ki-Bong
KB
D000192:Actinomycetales / Q000201:enzymology* / Q000235:genetics*; D002227:Carbazoles / Q000378:metabolism*; D003001:Cloning, Molecular; D005818:Genetic Engineering; D026121:Indole Alkaloids / Q000378:metabolism*; D005810:Multigene Family; D013302:Streptomyces / Q000201:enzymology / Q000235:genetics
D002227:Carbazoles; D026121:Indole Alkaloids; C049985:staurosporine aglycone