Research Center for Bio-based Chemistry, Korea Research Institute of Chemical Technology (KRICT), 406-30, Jongga-ro, Jung-gu, Ulsan, 44429, Republic of Korea.
Research Center for Bio-based Chemistry, Korea Research Institute of Chemical Technology (KRICT), 406-30, Jongga-ro, Jung-gu, Ulsan, 44429, Republic of Korea; Intelligent Sustainable Materials R&D Group, Research Institute of Sustainable Manufacturing System, Korea Institute of Industrial Technology (KITECH), Yandaegiro-gil, Ipjang-myeon, Seobuk-gu, Cheonan-si, Chungcheongnam-do, Republic of Korea.
Metab Eng. 2019 Dec;56:50-59. doi: 10.1016/j.ymben.2019.08.013. Epub 2019 Aug 21.
The endoplasmic reticulum (ER) is a dynamic organelle that synthesizes and folds proteins. An imbalance between the ER protein synthesis load and its folding capacity triggers the unfolded protein response, thereby restoring normal ER functions via size adjustment. Inspired by such inherent genetic programming events, we engineered Saccharomyces cerevisiae to expand the ER by overexpressing a key ER size regulatory factor, INO2. ER space expansion enhanced ER protein synthesis and folding capacity, and relieved metabolic constraints imposed by the limited enzyme abundance. Harnessing the yeast ER for metabolic engineering, we ultimately increased the production of squalene and cytochrome P450-mediated protopanaxadiol by 71-fold and 8-fold, compared to their respective control strains without overexpression of INO2. Furthermore, genome-wide transcriptome analysis of the ER-expanded strain revealed that the significant improvement in terpene production was associated with global rewiring of the metabolic network. Therefore, the yeast ER can be engineered as a specialized compartment for enhancing terpene production, representing new possibilities for the high-level production of other value-added chemicals.
内质网（ER）是一种动态细胞器，负责合成和折叠蛋白质。当 ER 蛋白合成负荷与其折叠能力之间的平衡被打破时，未折叠蛋白反应就会被触发，从而通过大小调整来恢复正常的 ER 功能。受这种固有遗传编程事件的启发，我们通过过度表达关键的 ER 大小调节因子 INO2 来工程改造酿酒酵母，从而扩大 ER 空间。ER 空间的扩大增强了 ER 蛋白的合成和折叠能力，并缓解了因有限的酶丰度而产生的代谢限制。我们利用酵母 ER 进行代谢工程改造，与未过度表达 INO2 的对照菌株相比，最终将鲨烯和细胞色素 P450 介导的原人参二醇的产量分别提高了 71 倍和 8 倍。此外，对 ER 扩展菌株的全基因组转录组分析表明，萜烯产量的显著提高与代谢网络的全局重新布线有关。因此，酵母 ER 可以被工程化为一种专门用于增强萜烯生产的特殊隔室，为其他高附加值化学品的高水平生产提供了新的可能性。
