Bacterial polyketides possess an enormous range of chemical diversity and biological function. Many polyketides such as tetracycline, epothilone, and rapamycin have been developed into key clinical pharmaceuticals in a broad range of therapeutic areas. Sequencing of bacterial genomes has shown that there are many more polyketide biosynthetic pathways than there are polyketides isolated from standard cultivation techniques. These genetically encoded polyketide natural products from cultivatable and uncultivatable bacteria represent one of the greatest remaining untapped reservoirs of new natural product diversity. To access this untapped diversity of polyketide products, a general method for heterologous expression of these pathways is needed. Heterologous expression has proven to be a valuable asset in the discovery, production, engineering, and characterization of bacterial secondary metabolites and the complex enzymology involved in their biosynthesis. Herein we discuss the development and investigation of two unique heterologous expression platforms utilizing host strains of Myxococcus xanthus and Escherichia coli. Using our developed heterologous hosts, we were able to produce the Streptomyces rimosus polyketide oxytetracycline. Through production of oxytetracycline in E .coli we have identified the potential of alternative transcription factors as regulators of secondary metabolism. Further investigation and development of alternative transcription factors as regulators of secondary metabolism in heterologous hosts could benefit the development of robust general methodology for the heterologous expression of polyketides.

Bacterial polyketides possess an enormous range of chemical diversity and biological function. Many polyketides such as tetracycline, epothilone, and rapamycin have been developed into key clinical pharmaceuticals in a broad range of therapeutic areas. Sequencing of bacterial genomes has shown that there are many more polyketide biosynthetic pathways than there are polyketides isolated from standard cultivation techniques. These genetically encoded polyketide natural products from cultivatable and uncultivatable bacteria represent one of the greatest remaining untapped reservoirs of new natural product diversity. To access this untapped diversity of polyketide products, a general method for heterologous expression of these pathways is needed. Heterologous expression has proven to be a valuable asset in the discovery, production, engineering, and characterization of bacterial secondary metabolites and the complex enzymology involved in their biosynthesis. Herein we discuss the development and investigation of two unique heterologous expression platforms utilizing host strains of Myxococcus xanthus and Escherichia coli. Using our developed heterologous hosts, we were able to produce the Streptomyces rimosus polyketide oxytetracycline. Through production of oxytetracycline in E .coli we have identified the potential of alternative transcription factors as regulators of secondary metabolism. Further investigation and development of alternative transcription factors as regulators of secondary metabolism in heterologous hosts could benefit the development of robust general methodology for the heterologous expression of polyketides.

Bacterial polyketides possess an enormous range of chemical diversity and biological function. Many polyketides such as tetracycline, epothilone, and rapamycin have been developed into key clinical pharmaceuticals in a broad range of therapeutic areas. Sequencing of bacterial genomes has shown that there are many more polyketide biosynthetic pathways than there are polyketides isolated from standard cultivation techniques. These genetically encoded polyketide natural products from cultivatable and uncultivatable bacteria represent one of the greatest remaining untapped reservoirs of new natural product diversity. To access this untapped diversity of polyketide products, a general method for heterologous expression of these pathways is needed. Heterologous expression has proven to be a valuable asset in the discovery, production, engineering, and characterization of bacterial secondary metabolites and the complex enzymology involved in their biosynthesis. Herein we discuss the development and investigation of two unique heterologous expression platforms utilizing host strains of Myxococcus xanthus and Escherichia coli. Using our developed heterologous hosts, we were able to produce the Streptomyces rimosus polyketide oxytetracycline. Through production of oxytetracycline in E .coli we have identified the potential of alternative transcription factors as regulators of secondary metabolism. Further investigation and development of alternative transcription factors as regulators of secondary metabolism in heterologous hosts could benefit the development of robust general methodology for the heterologous expression of polyketides.

Bacterial polyketides possess an enormous range of chemical diversity and biological function. Many polyketides such as tetracycline, epothilone, and rapamycin have been developed into key clinical pharmaceuticals in a broad range of therapeutic areas. Sequencing of bacterial genomes has shown that there are many more polyketide biosynthetic pathways than there are polyketides isolated from standard cultivation techniques. These genetically encoded polyketide natural products from cultivatable and uncultivatable bacteria represent one of the greatest remaining untapped reservoirs of new natural product diversity. To access this untapped diversity of polyketide products, a general method for heterologous expression of these pathways is needed. Heterologous expression has proven to be a valuable asset in the discovery, production, engineering, and characterization of bacterial secondary metabolites and the complex enzymology involved in their biosynthesis. Herein we discuss the development and investigation of two unique heterologous expression platforms utilizing host strains of Myxococcus xanthus and Escherichia coli. Using our developed heterologous hosts, we were able to produce the Streptomyces rimosus polyketide oxytetracycline. Through production of oxytetracycline in E .coli we have identified the potential of alternative transcription factors as regulators of secondary metabolism. Further investigation and development of alternative transcription factors as regulators of secondary metabolism in heterologous hosts could benefit the development of robust general methodology for the heterologous expression of polyketides.

With the increasing threat of multidrug resistant bacteria, there is a growing need to invent new drug classes that combat untreatable infections. Small molecule antibiotics have been successful in the past, but humanity is now losing the arms race against previously treatable pathogens. However, the number of clinically approved drugs targeting traditionally undruggable targets in bacteria remains low. New targets of complex protein-target interactions must be targeted for future pharmacological development. In an effort to create clinically viable biologics, the Verdine lab has developed a class of therapeutics called hydrocarbon stapled α-helical peptides; these peptides are known to affect protein-protein interactions by retaining secondary structure in vivo. Although this class of molecules has been extensively researched in cancer and viral therapies, there has been little work in bacteria due to the proposed endocytic method of entry. Moreover, DNA-binding stapled peptides have not been extensively investigated due the complexities in designing a peptide with gene selectivity. In an attempt to study peptides in bacteria, two stapled peptides based on the RpoN domain of σ54 and the FtsZ C-terminus have been synthesized. σ 54 is a DNA-binding co-factor of RNA polymerase (RNAP) and has been shown to regulate virulence and nitrogen and carbon metabolism. FtsZ is the structural unit of the contractile Z-ring that induces cell division. By designing stapled α-helical peptides to target these untraditional PPIs, we anticipate that these molecules may be used for future antimicrobial pharmacological development that treat multidrug resistant bacteria.