Selection of a Catalytically Active Enzyme In Vivo Via Phage Display of its Product

Selection of a biotin protein ligase by phage display using a combination of in vitro selection and in vivo enzymatic activity

We report the development of a phage display-based method for the direct selection of enzymatic activity by a combination of selection in vitro and an assay of enzymatic activity in vivo. We describe the selection of a biotin protein ligase (BPL) that specifically recognizes neurotensin as a substrate, as an example of the utility of our method. We constructed an enzyme library with a diversity of 8.8 x 10(6) by insertion of four randomized regions into a BPL backbone and used it for the selection of variant BPLs. We obtained an active BPL, which was identical to wild-type BPL, using the combination of selection in vitro and an assay of enzymatic activity in vivo. Our results indicate that our method is suitable for the selection of enzymes with specific functions of interest.

Selection strategies for improved biocatalysts

Enzymes have become an attractive alternative to conventional catalysts in numerous industrial processes. However, their properties do not always meet the criteria of the application of interest. Directed evolution is a powerful tool for adopting the characteristics of an enzyme. However, selection of the evolved variants is a critical step, and therefore new strategies to enable selection of the desired enzymatic activity have been developed. This review focuses on these novel strategies for selecting enzymes from large libraries, in particular those that are used in the synthesis of pharmaceutical intermediates and pharmaceuticals.