Bioconversion of deoxysugar moieties to the biosynthetic intermediates of daunorubicin in an engineered strain of Streptomyces coeruleobidus

The snogI Gene is Necessary for the Proper Functioning of the Nogalamycin Biosynthesis Pathway

Anthracycline drugs have multifunctional molecular structures, and small changes in the structure of the glycosyls around the chromophore affect their mechanism of action, pharmacokinetics, toxicity, anti-tumor activity, and many other significant parameters. DnrJ has a similar function to snogI but inverse stereoselectivity. SnogI encoding amino transferase was substituted for DnrJ for the purpose of obtaining nogalamycin analogues. We inactivated the snogI gene encoding an aminotransferase responsible for the formation of nogalamine and introduced the dnrJ gene encoding an aminotransferase responsible for the formation of daunosamine. We obtained the recombinant strain mLMX-3-100, in which the production of nogalamycin was disrupted. Interestingly, contrary to our predictions, no epi-nogalamycin was produced; nevertheless, the present study shows that the snogI gene is necessary for the proper functioning of the nogalamycin biosynthesis pathway. These data may provide a reference for further illustration of nogalamycin biosynthesis and its modification by way of combinatorial biosynthesis.biosynthesis and its modification by way of combinatorial biosynthesis.

Accessing Nature's diversity through metabolic engineering and synthetic biology

In this perspective, we highlight recent examples and trends in metabolic engineering and synthetic biology that demonstrate the synthetic potential of enzyme and pathway engineering for natural product discovery. In doing so, we introduce natural paradigms of secondary metabolism whereby simple carbon substrates are combined into complex molecules through “scaffold diversification”, and subsequent “derivatization” of these scaffolds is used to synthesize distinct complex natural products. We provide examples in which modern pathway engineering efforts including combinatorial biosynthesis and biological retrosynthesis can be coupled to directed enzyme evolution and rational enzyme engineering to allow access to the “privileged” chemical space of natural products in industry-proven microbes. Finally, we forecast the potential to produce natural product-like discovery platforms in biological systems that are amenable to single-step discovery, validation, and synthesis for streamlined discovery and production of biologically active agents.

Biotechnological advances in UDP-sugar based glycosylation of small molecules

Glycosylation of small molecules like specialized (secondary) metabolites has a profound impact on their solubility, stability or bioactivity, making glycosides attractive compounds as food additives, therapeutics or nutraceuticals. The subsequently growing market demand has fuelled the development of various biotechnological processes, which can be divided in the in vitro (using enzymes) or in vivo (using whole cells) production of glycosides. In this context, uridine glycosyltransferases (UGTs) have emerged as promising catalysts for the regio- and stereoselective glycosylation of various small molecules, hereby using uridine diphosphate (UDP) sugars as activated glycosyldonors. This review gives an extensive overview of the recently developed in vivo production processes using UGTs and discusses the major routes towards UDP-sugar formation. Furthermore, the use of interconverting enzymes and glycorandomization is highlighted for the production of unusual or new-to-nature glycosides. Finally, the technological challenges and future trends in UDP-sugar based glycosylation are critically evaluated and summarized.