Bu Ru, Li Zhenze, Qin Qiyu, Bai Huashan, Meng Can, Wei Ruihang, Chen Xinglin, Wu Shanguang, Kashif Muhammad, He Sheng, Jiang Chengjian
State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, Nanning 530004, China.
Guangxi Key Laboratory for Green Processing of Sugar Resources, Guangxi College Key Laboratory of Innovation Research on Medical and Engineering Integration, Liuzhou Key Laboratory of Guizhong Characteristic Medicinal Resources, Medical College, College of Biological and Chemical Engineering, Guangxi University of Science and Technology, Liuzhou 545006, China.
J Agric Food Chem. 2025 Jan 8;73(1):507-520. doi: 10.1021/acs.jafc.4c08573. Epub 2024 Dec 19.
Cyclo(Pro-Val) is a diketopiperazine (DKP) found widespread in marine microbes and resulting food products. With new bioactivities of cyclo(Pro-Val) being continually discovered, its potential applications in agriculture and food are becoming more evident, highlighting the need for efficient and practical methods to produce these compounds. However, the biosynthesis mechanisms of cyclo(Pro-Val), particularly in probiotics, remain unclear, and the functional identification of nonribosomal peptide synthases (NRPS) is still limited. This study presents a new efficient cyclo(Pro-Val) production system using the marine probiotic () GXDK6 as a chassis cell. We further characterized an NRPS-like gene, , which spans 3825 bp and encodes an l-2-amino-hexanedioic acid reductase (Lys2p) consisting of 1274 amino acids. A novel macrocyclization mechanism was revealed involving the peptide N-terminal and C-terminal imines mediated by Lys2p through nucleophilic reactions. Overexpressing in GXDK6 resulted in a 45.5% increase in cyclo(Pro-Val) production, while knockout completely halted its synthesis. This study revealed a novel metabolic regulatory pathway and biosynthetic mechanism for cyclo(Pro-Val) in marine yeast GXDK6. Refactoring the biosynthetic pathway in yeast through provides an alternative approach for producing cyclo(Pro-Val).
环（脯氨酸-缬氨酸）是一种二酮哌嗪（DKP），广泛存在于海洋微生物及其衍生的食品中。随着环（脯氨酸-缬氨酸）新生物活性的不断发现，其在农业和食品领域的潜在应用日益显著，这凸显了开发高效实用的这些化合物生产方法的必要性。然而，环（脯氨酸-缬氨酸）的生物合成机制，尤其是在益生菌中的机制，仍不清楚，非核糖体肽合成酶（NRPS）的功能鉴定也仍然有限。本研究提出了一种新的高效环（脯氨酸-缬氨酸）生产系统，以海洋益生菌（）GXDK6作为底盘细胞。我们进一步对一个类NRPS基因进行了表征，该基因跨度为3825 bp，编码一种由1274个氨基酸组成的L-2-氨基己二酸还原酶（Lys2p）。揭示了一种新的大环化机制，涉及Lys2p通过亲核反应介导的肽N端和C端亚胺。在GXDK6中过表达该基因导致环（脯氨酸-缬氨酸）产量增加45.5%，而敲除该基因则完全停止其合成。本研究揭示了海洋酵母GXDK6中环（脯氨酸-缬氨酸）的一种新的代谢调控途径和生物合成机制。通过该基因对酵母中的生物合成途径进行重构，为环（脯氨酸-缬氨酸）的生产提供了一种替代方法。
