萜类合成酶定向进化的新思路

萜类化合物是天然产物中种类最多且主要存在于植物和微生物体内的一类化合物。随着越来越多具有应用价值的萜类化合物被挖掘,其应用前景引起了人们的关注,但由于含量低、提取成本高等缺点,因此制约了萜类化合物的广泛应用。合成生物学的兴起,为异源合成具有应用价值的萜类化合物提供了新思路,使构建定向、高效的微生物细胞工厂成为现实。萜类合成酶常作为萜类化合物异源合成代谢调控的靶酶,但天然的萜类合成酶存在催化效率低、底物专一性差、立体/区域选择性差、稳定性差等问题,严重影响萜类化合物的产量。萜类合成酶的定向进化可以有效地解决上述问题,为实现微生物细胞工厂异源、高效合成萜类化合物奠定基础。本文综述了近年来酶的定向进化技术的最新进展及应用,并提出了萜类合成酶定向进化的策略。

Innovations for directed evolution of terpenoid synthases

Terpenoids are mostly existing compounds in natural products like plants and microorganisms. The application prospect of terpenoids attracts much attention owing to more and more valuable terpenoids discovered. However, limited yield and high extraction cost of terpenoids restrict their wide applications. The rise of synthetic biology has provided new ideas for biosynthesis of valuable terpenoids using targeted and high efficient microbial cell factories. Although terpenoid synthases are widely used as target enzymes in metabolic regulation of terpenoids biosynthesis, many natural terpenoid synthases have some disadvantages, such as insufficient catalytic activity, poor substrate specificity, poor regio-or stereoselectivity, poor stability and so on, which unfavorably affect the yield of terpenoids. To solve above problems, directed evolution of terpenoid synthases has been applied, which will have profound impact on biosynthesis of terpenoids by microbial cell factories. This review summarizes recent advances and their applications in directed evolution of enzymes. Meanwhile, the strategies for directed evolution of terpenoid synthases are proposed.