Roddan Rebecca, Sula Altin, Méndez-Sánchez Daniel, Subrizi Fabiana, Lichman Benjamin R, Broomfield Joseph, Richter Michael, Andexer Jennifer N, Ward John M, Keep Nicholas H, Hailes Helen C
Department of Biological Sciences, Institute of Structural and Molecular Biology, Birkbeck College, London, WC1E 7HX, UK.
Department of Chemistry, Christopher Ingold Building, University College London, London, WC1H 0AJ, UK.
Commun Chem. 2020 Nov 13;3(1):170. doi: 10.1038/s42004-020-00416-8.
The 1-aryl-tetrahydroisoquinoline (1-aryl-THIQ) moiety is found in many biologically active molecules. Single enantiomer chemical syntheses are challenging and although some biocatalytic routes have been reported, the substrate scope is limited to certain structural motifs. The enzyme norcoclaurine synthase (NCS), involved in plant alkaloid biosynthesis, has been shown to perform stereoselective Pictet-Spengler reactions between dopamine and several carbonyl substrates. Here, benzaldehydes are explored as substrates and found to be accepted by both wild-type and mutant constructs of NCS. In particular, the variant M97V gives a range of (1 S)-aryl-THIQs in high yields (48-99%) and e.e.s (79-95%). A co-crystallised structure of the M97V variant with an active site reaction intermediate analogue is also obtained with the ligand in a pre-cyclisation conformation, consistent with (1 S)-THIQs formation. Selected THIQs are then used with catechol O-methyltransferases with exceptional regioselectivity. This work demonstrates valuable biocatalytic approaches to a range of (1 S)-THIQs.
1-芳基-四氢异喹啉（1-aryl-THIQ）部分存在于许多生物活性分子中。单一对映体的化学合成具有挑战性，尽管已报道了一些生物催化途径，但其底物范围仅限于某些结构基序。参与植物生物碱生物合成的酶去甲乌药碱合酶（NCS）已被证明能在多巴胺和几种羰基底物之间进行立体选择性的 Pictet-Spengler 反应。在此，研究了苯甲醛作为底物，发现野生型和突变型 NCS 构建体均能接受。特别是，变体 M97V 能以高产率（48-99%）和对映体过量值（79-95%）生成一系列（1 S）-芳基-THIQ。还获得了 M97V 变体与活性位点反应中间体类似物的共结晶结构，配体处于预环化构象，这与（1 S）-THIQ 的形成一致。然后将选定的 THIQ 与儿茶酚 O-甲基转移酶一起使用，具有出色的区域选择性。这项工作展示了合成一系列（1 S）-THIQ 的有价值的生物催化方法。
