Rational design for improving production biological activity and identification of natural products.

摘要

Millions of years of evolution have tuned living organisms to efficiently utilize renewable sources of energy. Metabolic engineers are thus attempting to utilize the efficiency of this system for economical production of a variety of chemicals, which have pharmaceutical or commercial value. Genetically tractable organisms like yeast and E. coli, are being utilized as production platforms for molecules of human value. This attempt at utilizing microbial organisms as cell factories has been greatly bolstered by the advent of recombinant DNA technology. Entire metabolic pathways have been expressed in heterologous hosts and the further fine-tuning of the resulting recombinant organisms has resulted in production of high titers of such important chemicals. While much needs to be learnt about quick optimization of microbial cells for high-yielding production of molecules of our interest, in recent years, the engineering of biological systems has expanded in other directions. We are now capable of creating novel metabolic pathways by hand picking biosynthetic enzymes from different sources to generate non-natural molecules or altering the biochemical properties of enzymes to modify natural products. Tailoring enzymes, fusion proteins and protein engineering techniques have been employed to diversify pharmaceutically important small molecules.;In this work, we employed metabolic engineering and systems biology to improve the yields of plant polyketide resveratrol in E. coli by redirecting carbon flux into the heterologous pathway. Further, we attempted to generate novel polyketides by structure-based engineering of stilbene synthase (STS), a type III plant polyketide synthase. Finally, we diversified the resveratrol monomer into two dimers (resveratrol-trans-dihydrodimer and pallidol) via in vitro oligomerization reaction. Resveratrol- trans-dihydrodimer was shown to be an active antimicrobial, having significantly higher potency than the monomer. Apart from that, we also attempted to employ metabolomics approach to characterize the secondary metabolites produced by a strain of marine bacteria, Pseudoalteromonas ATCC 29581.