Investigation of the effects of actinorhodin biosynthetic gene cluster expression and a rpoB point mutation on the metabolome of Streptomyces coelicolor M1146

Pseudouridimycin (PUM) was recently discovered from Streptomyces sp. DSM26212 as a novel bacterial nucleoside analog that competes with UTP for access to the RNA polymerase (RNAP) active site, thereby inhibiting bacterial RNAP by blocking transcription. This represents a novel antibacterial mode of action and it is known that PUM inhibits bacterial RNAP in vitro, inhibits bacterial growth in vitro, and was active in vivo in a mouse infection model of Streptococcus pyogenes peritonitis. The biosynthetic gene cluster (BGC) was previously identified and characterized by knockout experiments. However, the minimal set of genes necessary for PUM production was not proposed. To identify the minimal BGC and to create a plug-and-play production platform for PUM and its biosynthetic precursors, several versions of a redesigned PUM BGC were generated and expressed in the heterologous host Streptomyces coelicolor M1146 under control of strong promotors. Heterologous expression allowed identification of the putative serine/threonine kinase PumF as an enzyme essential for heterologous PUM production and thus corroboration of the PUM minimal BGC.

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Analysis of the Tunicamycin Biosynthetic Gene Cluster ofStreptomyces chartreusisReveals New Insights into Tunicamycin Production and Immunity

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.00130-18 ◽

2018 ◽

Vol 62 (8) ◽

Cited By ~ 10

Author(s):

David Widdick ◽

Sylvain F. Royer ◽

Hua Wang ◽

Natalia M. Vior ◽

Juan Pablo Gomez-Escribano ◽

...

Keyword(s):

Gene Cluster ◽

Streptomyces Coelicolor ◽

Biosynthetic Gene Cluster ◽

Transcriptional Analysis ◽

Efficient Production ◽

Primary Metabolism ◽

Biosynthetic Gene ◽

Content Type ◽

High Degree ◽

Single Operon

ABSTRACTThe tunicamycin biosynthetic gene cluster ofStreptomyces chartreusisconsists of 14 genes (tunAtotunN) with a high degree of apparent translational coupling. Transcriptional analysis revealed that all of these genes are likely to be transcribed as a single operon from two promoters,tunp1 andtunp2. In-frame deletion analysis revealed that just six of these genes (tunABCDEH) are essential for tunicamycin production in the heterologous hostStreptomyces coelicolor, while five (tunFGKLN) with likely counterparts in primary metabolism are not necessary, but presumably ensure efficient production of the antibiotic at the onset of tunicamycin biosynthesis. Three genes are implicated in immunity, namely,tunIandtunJ, which encode a two-component ABC transporter presumably required for export of the antibiotic, andtunM, which encodes a putativeS-adenosylmethionine (SAM)-dependent methyltransferase. Expression oftunIJortunMinS. coelicolorconferred resistance to exogenous tunicamycin. The results presented here provide new insights into tunicamycin biosynthesis and immunity.

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Cloning, sequencing and heterologous expression of the medermycin biosynthetic gene cluster of Streptomyces sp. AM-7161: towards comparative analysis of the benzoisochromanequinone gene clusters

Microbiology ◽

10.1099/mic.0.26310-0 ◽

2003 ◽

Vol 149 (7) ◽

pp. 1633-1645 ◽

Cited By ~ 84

Author(s):

Koji Ichinose ◽

Makoto Ozawa ◽

Keiko Itou ◽

Kanako Kunieda ◽

Yutaka Ebizuka

Keyword(s):

Heterologous Expression ◽

Gene Cluster ◽

Polyketide Synthase ◽

Acyl Carrier Protein ◽

Streptomyces Coelicolor ◽

Gene Clusters ◽

Biosynthetic Gene Cluster ◽

Carrier Protein ◽

Biosynthetic Gene ◽

Six Genes

Medermycin is a Streptomyces aromatic C-glycoside antibiotic classified in the benzoisochromanequinones (BIQs), which presents several interesting biosynthetic problems concerning polyketide synthase (PKS), post-PKS tailoring and deoxysugar pathways. The biosynthetic gene cluster for medermycin (the med cluster) was cloned from Streptomyces sp. AM-7161. Completeness of the clone was proved by the heterologous expression of a cosmid carrying the entire med cluster in Streptomyces coelicolor CH999 to produce medermycin. The DNA sequence of the cosmid (36 202 bp) revealed 34 complete ORFs, with an incomplete ORF at either end. Functional assignment of the deduced products was made for PKS and biosynthetically related enzymes, tailoring steps including strereochemical control, oxidation, angolosamine pathway, C-glycosylation, and regulation. The med cluster was estimated to be about 30 kb long, covering 29 ORFs. An unusual characteristic of the cluster is the disconnected organization of the minimal PKS genes: med-ORF23 encoding the acyl carrier protein is 20 kb apart from med-ORF1 and med-ORF2 for the two ketosynthase components. Secondly, the six genes (med-ORF14, 15, 16, 17, 18 and 20) for the biosynthesis of the deoxysugar, angolosamine, are all contiguous. Finally, the finding of a glycosyltransferase gene, med-ORF8, suggests a possible involvement of conventional C-glycosylation in medermycin biosynthesis. Comparison among the three complete BIQ gene clusters – med and those for actinorhodin (act) and granaticin (gra) – revealed some common genes whose deduced functions are unavailable from database searches (the ‘unknowns’). An example is med-ORF5, a homologue of actVI-ORF3 and gra-ORF18, which was highlighted by a recent proteomic analysis of S. coelicolor A3(2).

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Regulation of valanimycin biosynthesis in Streptomyces viridifaciens: characterization of VlmI as a Streptomyces antibiotic regulatory protein (SARP)

Microbiology ◽

10.1099/mic.0.033167-0 ◽

2010 ◽

Vol 156 (2) ◽

pp. 472-483 ◽

Cited By ~ 15

Author(s):

Ram P. Garg ◽

Ronald J. Parry

Keyword(s):

Gene Cluster ◽

Streptomyces Coelicolor ◽

Regulatory Gene ◽

Regulatory Protein ◽

Biosynthetic Gene Cluster ◽

Positive Control ◽

Biosynthetic Gene ◽

Direct Repeats ◽

Expression Plasmid ◽

Intergenic Regions

Streptomyces antibiotic regulatory proteins (SARPs) have been shown to activate transcription by binding to a tandemly arrayed set of heptameric direct repeats located around the −35 region of their cognate promoters. Experimental evidence is presented here showing that vlmI is a regulatory gene in the valanimycin biosynthetic gene cluster of Streptomyces viridifaciens and encodes a protein belonging to the SARP family. The organization of the valanimycin biosynthetic gene cluster suggests that the valanimycin biosynthetic genes are located on three potential transcripts, vlmHORBCD, vlmJKL and vlmA. Disruption of vlmI abolished valanimycin biosynthesis. Western blot analyses showed that VlmR and VlmA are absent from the vlmI mutant and that the production of VlmK is severely diminished. These results demonstrate that the expression of these genes from the three potential transcripts is under the positive control of VlmI. The vlmA–vlmH and vlmI–vlmJ intergenic regions both exhibit a pattern of heptameric direct repeats. Gel shift assays with VlmI overproduced in Escherichia coli as a C-terminal FLAG-tagged protein clearly demonstrated that VlmI binds to DNA fragments from both regions that contain these heptameric repeats. When a high-copy-number vlmI expression plasmid was introduced into Streptomyces coelicolor M512, which contains mutations in the undecylprodigiosin and actinorhodin activators redD and actII-orf4, undecylprodigiosin production was restored, showing that vlmI can complement a redD mutation. Introduction of the same vlmI expression plasmid into an S. viridifaciens vlmI mutant restored valanimycin production to wild-type levels.

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