Mutational biosynthesis of tacrolimus analogues by fkbO deletion mutant of Streptomyces sp. KCTC 11604BP

Bioengineering of Anti-Inflammatory Natural Products

Inflammatory processes occur as a generic response of the immune system and can be triggered by various factors, such as infection with pathogenic microorganisms or damaged tissue. Due to the complexity of the inflammation process and its role in common diseases like asthma, cancer, skin disorders or Alzheimer's disease, anti-inflammatory drugs are of high pharmaceutical interest. Nature is a rich source for compounds with anti-inflammatory properties. Several studies have focused on the structural optimization of natural products to improve their pharmacological properties. As derivatization through total synthesis is often laborious with low yields and limited stereoselectivity, the use of biosynthetic, enzyme-driven reactions is an attractive alternative for synthesizing and modifying complex bioactive molecules. In this minireview, we present an outline of the biotechnological methods used to derivatize anti-inflammatory natural products, including precursor-directed biosynthesis, mutasynthesis, combinatorial biosynthesis, as well as whole-cell and in vitro biotransformation.

How Chorismatases Regulate Distinct Reaction Channels in a Single Conserved Active Pocket: Mechanistic Analysis with QM/MM (ONIOM) Investigations

The FkbO and Hyg5 subfamilies of chorismatases share the same active-site architectures, but perform distinct reaction mechanisms, that is, FkbO employs a hydrolysis reaction whereas Hyg5 proceeds through an intramolecular mechanism. Despite extensive research efforts, the detailed mechanism of the product selectivity in chorismatases need to be further unmasked. In this study, the effects of the A/G residue group (A244^FkbO /G240^Hyg5 ) and the V/Q residue group (V209^FkbO /Q201^Hyg5 ) on the catalytic mechanisms are investigated by employing molecular dynamics simulations and hybrid quantum mechanical/molecular mechanical (QM/MM) calculations of the two wild-type models (FkbO/CHO and Hyg5/CHO; CHO=chorismate) and four mutants models (A244G-FkbO/CHO and G240A-Hyg5/CHO; V209Q-FkbO/CHO and Q201V-Hyg5/CHO). Our results showed that the A/G residue group mentioned by previous works would cause changes in the binding states of the substrate and the orientation of the catalytic glutamate, but only these changes affect the product selectivity in chorismatases limitedly. Interestingly, the distal V/Q residue group, which determines the internal water self-regulating ability at the active site, has significant impact on the selectivity of the catalytic mechanisms. The V/Q residue group is suggested to be an important factor to control the catalytic activities in chorismatases. The results are consistent with biochemical and structural experiments, providing novel insight into the mechanism of product selectivity in chorismatases.

The biosynthetic pathway of FK506 and its engineering: from past achievements to future prospects

FK506, a 23-membered macrolide produced by several Streptomyces species, is an immunosuppressant widely used to prevent the rejection of transplanted organs. In addition, FK506 and its analogs possess numerous promising therapeutic potentials including antifungal, neuroprotective, and neuroregenerative activities. Herein, we introduce the biological activities and mechanisms of action of FK506 and discuss recent progress made in understanding its biosynthetic pathway, improving production, and in the mutasynthesis of diverse analogs. Perspectives highlighting further strain improvement and structural diversification aimed at generating more analogs with improved pharmaceutical properties will be emphasized.