Overexpression of SRO_3163, a homolog of Streptomyces antibiotic regulatory protein, induces the production of novel cyclohexene-containing enamide in Streptomyces rochei

Abstract

Streptomyces antibiotic regulatory proteins (SARPs) are well characterized as transcriptional activators for secondary metabolites in Streptomyces species. Streptomyces rochei 7434AN4 harbors 15 SARP genes, among which 3 were located on a giant linear plasmid pSLA2-L and others were on the chromosome. Some SARP genes were cloned into an integrative thiostrepton-inducible vector pIJ8600, and their recombinants were cultivated. The recombinant of SARP gene, SRO_3163, accumulated a UV-active compound YM3163-A, which was not detected in the parent strain and other SARP recombinants. Its molecular formula was established to be C8H11NO. Extensive NMR analysis revealed that YM3163-A is a novel enamide, 2-(cyclohex-2-en-1-ylidene)acetamide, and its structure was confirmed by chemical synthesis including Horner-Wadsworth-Emmons reaction and ammonolysis.

Promoter engineering of natural product biosynthetic gene clusters in actinomycetes: concepts and applications

“…The thiostrepton inducible system has been used in actinomycetes to elicit cryptic metabolite production by regulatory gene overexpression and to control the expression of toxic proteins. 74,75 High-level leaky expression in the absence of thiostrepton and the use of the thiostrepton resistance gene tsr due to the strong antibacterial activity of the thiostrepton inducer are drawbacks of this system.…”

Expression of Syo_1.56 SARP Regulator Unveils Potent Elasnin Derivatives with Antibacterial Activity

“…32 In a recent study, the expression of SRO_3163, a SARP regulator, in Streptomyces rochei resulted in the identification of a novel enamide compound, 2-(cyclohex-2-en-1-ylidene)acetamide. 33 SARPs are recognized as pathway-specific regulators due to their ability to selectively activate the corresponding gene clusters.…”

“…Additionally, the accumulation of demeclocycline was significantly enhanced by the expression of the ctcB SARP regulator in Streptomyces aureofaciens . In a recent study, the expression of SRO_3163, a SARP regulator, in Streptomyces rochei resulted in the identification of a novel enamide compound, 2-(cyclohex-2-en-1-ylidene)­acetamide . SARPs are recognized as pathway-specific regulators due to their ability to selectively activate the corresponding gene clusters.…”

Isolation of Hydrazide-alkenes with Different Amino Acid Origins from an Azoxy-alkene-Producing Mutant of Streptomyces rochei 7434AN4

“…Mutation of the lankacidin biosynthesis gene lkcA led to the accumulation of three polyketides: pentamycin, citreodiol, and epi -citreodiol . Overexpression of the Streptomyces antibiotic regulatory protein (SARP) type activator gene SRO_3163 caused accumulation of novel enamide . Multiple mutations of regulatory genes srrY and srrC led to the accumulation of three 4-monosubstituted butyrolactones .…”

“…21 Overexpression of the Streptomyces antibiotic regulatory protein (SARP) type activator gene SRO_3163 caused accumulation of novel enamide. 22 Multiple mutations of regulatory genes srrY and srrC led to the accumulation of three 4-monosubstituted butyrolactones. 23 Notably, strain KA57 harboring triple mutations in the transcriptional repressor srrB and two biosynthetic genes for lankacidin and lankamycin produced an azoxy-alkene compound, KA57A (1), which was not detected in a parent strain or other single or double mutants.…”