Ginsenoside Rh2 (3β-O-Glc-protopanaxadiol), a trace but an important pharmacological component of ginseng, has exhibited excellent medicinal potential. Many studies have found that the synthesis of Rh2 by UDP-glucosyltransferase (UGT) is an alternative production strategy. In this study, Yjic from B. subtilis 168 was found to synthesize ginsenoside F12 (3β,12β-Di-O-Glc-protopanaxadiol) and Rh2 at a ratio of 7:3. Yjic regioselectivity toward Rh2 synthesis was successfully improved using a semi-rational design including structure-guided alanine scanning and saturation mutations. As a result, mutant M315F was found to efficiently synthesize Rh2 (~99%) and block the further glycosylation of C12-OH. The circulation of UDPG was achieved by combining M315F with AtSuSy through a cascade reaction. Furthermore, an extraordinarily high yield of Rh2 (3.7 g/L) was attained in an aqueous solvent system with 17% DMSO (v/v) through the fed-batch feeding of PPD. This study presents the high potential for the oriented preparation of ginsenoside Rh2.

中文翻译：

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通过用蔗糖合酶编译UGT-Yjic突变体，定向有效地从PPD合成人参皂甙Rh2。

人参微量的人参皂苷Rh2（3β-O-Glc-原人参二醇）是重要的药理成分，具有极好的药用潜力。许多研究发现，通过UDP-葡萄糖基转移酶（UGT）合成Rh2是另一种生产策略。在这项研究中，枯草芽孢杆菌168的Yjic被发现以7：3的比例合成人参皂苷F12（3β，12β-Di-O-Glc-原托纳糖醇）和Rh2。使用包括结构导向的丙氨酸扫描和饱和突变在内的半理性设计，成功地提高了对Rh2合成的Yjic区域选择性。结果，发现突变体M315F有效合成Rh2（〜99％）并阻断C12-OH的进一步糖基化。UDPG的循环是通过级联反应将M315F与AtSuSy结合而实现的。此外，Rh2的产量极高（3。通过PPD的分批补料进料，在含有17％DMSO（v / v）的水性溶剂系统中达到7 g / L）。这项研究为人参皂苷Rh2的定向制备提供了很高的潜力。