Institute of Materia Medica, College of Pharmaceutical Sciences, Zhejiang University, 388 Yu Hang Tang Road, Hangzhou 310058, P. R. China.
Chem Biodivers. 2010 Apr;7(4):860-70. doi: 10.1002/cbdv.201000052.
Strictosidine synthase (STR1) catalyzes the stereoselective formation of 3alpha(S)-strictosidine from tryptamine and secologanin. Strictosidine is the key intermediate in the biosynthesis of 2,000 plant monoterpenoid indole alkaloids, and it is a key precursor of enzyme-mediated synthesis of alkaloids. An improved expression system is described which leads to optimized His(6)-STR1 synthesis in Escherichia coli. Optimal production of STR1 was achieved by determining the impact of co-expression of chaperones pG-Tf2 and pG-LJE8. The amount and activity of STR1 was doubled in the presence of chaperone pG-Tf2 alone. His(6)-STR1 immobilized on Ni-NTA can be used for enzymatic synthesis of strictosidines on a preparative scale. With the newly co-expressed His(6)-STR1, novel 3alpha(S)-12-azastrictosidine was obtained by enzymatic catalysis of 7-azatryptamine and secologanin. The results obtained are of significant importance for application to chemo-enzymatic approaches leading to diversification of alkaloids with novel improved structures.
苦马豆素合酶（STR1）能够立体选择性地催化色胺和马刺旦醇生成 3α（S）-苦马豆素。苦马豆素是 2000 种植物单萜吲哚生物碱生物合成的关键中间体，也是酶介导的生物碱合成的关键前体。本文描述了一种改良的表达系统，该系统可优化大肠杆菌中 His（6）-STR1 的合成。通过确定伴侣蛋白 pG-Tf2 和 pG-LJE8 的共表达对 STR1 生产的影响，实现了 STR1 的最佳生产。单独存在伴侣蛋白 pG-Tf2 时，STR1 的含量和活性增加了一倍。固定在 Ni-NTA 上的 His（6）-STR1 可用于在制备规模上进行苦马豆素的酶促合成。利用新共表达的 His（6）-STR1，通过 7-氮杂色胺和马刺旦醇的酶催化作用，获得了新型的 3α（S）-12-氮杂苦马豆素。这些结果对于应用化学酶法途径导致具有新型改良结构的生物碱多样化具有重要意义。
