Luo Yan, Jiang Yaozhu, Chen Linhao, Li Chun, Wang Ying
Key Laboratory of Medical Molecule Science and Pharmaceutics Engineering, Institute of Biochemical Engineering, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing, China.
Key Laboratory for Industrial Biocatalysis, Ministry of Education, Department of Chemical Engineering, Tsinghua University, Beijing, China.
Synth Syst Biotechnol. 2022 Oct 25;8(1):20-32. doi: 10.1016/j.synbio.2022.10.001. eCollection 2023 Mar.
Triterpenoids are a class of natural products widely used in fields related to medicine and health due to their biological activities such as hepatoprotection, anti-inflammation, anti-viral, and anti-tumor. With the advancement in biotechnology, microorganisms have been used as cell factories to produce diverse natural products. Despite the significant progress that has been made in the construction of microbial cell factories for the heterogeneous biosynthesis of triterpenoids, the industrial production of triterpenoids employing microorganisms has been stymied due to the shortage of efficient enzymes as well as the low expression and low catalytic activity of heterologous proteins in microbes. Protein engineering has been demonstrated as an effective way for improving the specificity, catalytic activity, and stability of the enzyme, which can be employed to overcome these challenges. This review summarizes the current progress in the studies of Oxidosqualene cyclases (OSCs), cytochrome P450s (P450s), and UDP-glycosyltransferases (UGTs), the key enzymes in the triterpenoids synthetic pathway. The main obstacles restricting the efficient catalysis of these key enzymes are analyzed, the applications of protein engineering for the three key enzymes in the microbial synthesis of triterpenoids are systematically reviewed, and the challenges and prospects of protein engineering are also discussed.
三萜类化合物是一类天然产物，因其具有保肝、抗炎、抗病毒和抗肿瘤等生物活性而广泛应用于医药和健康相关领域。随着生物技术的进步，微生物已被用作细胞工厂来生产各种天然产物。尽管在构建用于三萜类化合物异源生物合成的微生物细胞工厂方面已经取得了重大进展，但由于缺乏高效酶以及微生物中异源蛋白的低表达和低催化活性，利用微生物进行三萜类化合物的工业化生产受到了阻碍。蛋白质工程已被证明是提高酶的特异性、催化活性和稳定性的有效方法，可用于克服这些挑战。本文综述了三萜类化合物合成途径中的关键酶——氧化鲨烯环化酶（OSCs）、细胞色素P450（P450s）和尿苷二磷酸糖基转移酶（UGTs）的研究现状。分析了限制这些关键酶高效催化的主要障碍，系统综述了蛋白质工程在三萜类化合物微生物合成中对这三种关键酶的应用，并讨论了蛋白质工程面临的挑战和前景。
