Optimization of the experimental parameters of the ligase cycling reaction

HyperXpress: Rapid Single Vessel DNA Assembly and Protein Production in Microliterscale

Rapid prototyping of biological functions has the common aim of generating, screening, and selecting variant libraries as quickly as possible. This approach is now to be extended by the HyperXpress workflow, which connects ligase cycling reaction for DNA assembly, multiply-primed rolling circle amplification for signal amplification, and cell-free protein synthesis to a single vessel reaction in the lower µl scale. After substantial optimization of the method a proof-of-principle demonstrating the high flexibility of HyperXpress for semi-rational protein engineering by expanding, reducing, and replacing β-strands of three different green fluorescent proteins is described. These single-day experiments resulted in six functional, new-to-nature GFP prototypes.

Recent Advances in Strategies for the Cloning of Natural Product Biosynthetic Gene Clusters

Microbial natural products (NPs) are a major source of pharmacological agents. Most NPs are synthesized from specific biosynthetic gene clusters (BGCs). With the rapid increase of sequenced microbial genomes, large numbers of NP BGCs have been discovered, regarded as a treasure trove of novel bioactive compounds. However, many NP BGCs are silent in native hosts under laboratory conditions. In order to explore their therapeutic potential, a main route is to activate these silent NP BGCs in heterologous hosts. To this end, the first step is to accurately and efficiently capture these BGCs. In the past decades, a large number of effective technologies for cloning NP BGCs have been established, which has greatly promoted drug discovery research. Herein, we describe recent advances in strategies for BGC cloning, with a focus on the preparation of high-molecular-weight DNA fragment, selection and optimization of vectors used for carrying large-size DNA, and methods for assembling targeted DNA fragment and appropriate vector. The future direction into novel, universal, and high-efficiency methods for cloning NP BGCs is also prospected.