ε-聚赖氨酸生物合成及其产生菌遗传转化研究进展

ε-聚赖氨酸(ε-poly-L-lysine,ε-PL)是由25-35个L-赖氨酸(L-lysine)通过α-ε酰胺键连接的具有很强抗菌活性的聚合物,是自然界中迄今为止仅发现的2种均聚氨基酸(ε-聚赖氨酸和γ-聚谷氨酸)之一。目前,研究发现ε-聚赖氨酸的合成酶是一种非核糖体肽合成酶,它催化前体物质L-lysine经多轮缩合反应合成链长不均一的ε-聚赖氨酸,与I型聚酮合成酶的合成过程相似。ε-聚赖氨酸的合成不受降解酶控制。同时,针对产生菌遗传转化的穿梭质粒载体pLAE001和pLAE003已构建成功,为进一步探索ε-聚赖氨酸生物合成提供了条件。本文主要就ε-聚赖氨酸生物合成及产生菌遗传转化体系进行综述。另外,扼要介绍了作者所在课题组的相关研究工作、取得的进展并提出了相应的见解,论文最后部分对组合生物合成在ε-PL产生菌菌种改造中的应用前景进行了探讨。

Progress in biosynthesis of epsilon-poly-L-lysine and genetic transformation for epsilon-poly-L-lysine producer--a review

Epsilon-Poly-L-lysine (epsilon-PL) is a polymer with strong antimicrobial activity and consists of 25-35 L-lysine monomers linked via epsilon-amino-alpha-carboxyl peptide bond. This polymer is one of only two homo-poly (amino acid) polymers known in nature. To date, the biosynthesis mechanism of epsilon-PL was remained unclear. Recently, epsilon-PL synthetase was identified as a nonribosomal peptide synthetase and it utilized L-lysine to synthesize epsilon-PLs of various chain length by iteratively condensing reaction, which was similar to type I polyketide synthase and was not determined by epsilon-PL-degrading enzyme. Meanwhile, the shutter vectors pLAE001 and pLAE003, special for epsilon-PL producer have been constructed, which is significant for studying epsilon-PL biosynthesis. In this review, the biosynthesis of epsilon-PL and the genetic transformation were introduced. Also, the study in our group was presented and the views related to e-PL study were raised. Finally, the prospect of application of combinational biosynthesis in epsilon-PL-producing strain improvement was also discussed considering epsilon-PL synthetase is a nonribosomal peptide synthetase containing several modules.