Transcriptional regulators of secondary metabolite biosynthesis in Streptomyces.

In the post-genome era, great progress has been made in metabolic engineering using recombinant DNA technology to enhance the production of high-value products by Streptomyces. With the development of microbial genome sequencing techniques and bioinformatic tools, a growing number of secondary metabolite (SM) biosynthetic gene clusters in Streptomyces and their biosynthetic logics have been uncovered and elucidated. In order to increase our knowledge about transcriptional regulators in SM of Streptomyces, this review firstly makes a comprehensive summary of the characterized factors involved in enhancing SM production and awakening SM biosynthesis. Future perspectives on transcriptional regulator engineering for new SM biosynthesis by Streptomyces are also provided.

Catalyst-free and visible light promoted trifluoromethylation and perfluoroalkylation of uracils and cytosines.

Fluoroalkylated enaminones, such as trifluridine and 5-trifluoromethyluracil, have widespread applications in pharmaceuticals and agrochemicals. Although these kinds of pharmaceutical agent often bear CF3 and perfluoroalkyl motifs in the core structure, access to such analogues typically requires multi-step synthesis. Here, we report a mild, metal-free and operationally simple strategy for the direct perfluoroalkylation of uracils, cytosines and pyridinones through a visible-light induced pathway from perfluoroalkyl iodides. This photochemical transformation features synthetic simplicity, mild reaction conditions without any photoredox catalyst, and high functional group tolerance, providing a facile route for applications in medicinal chemistry.