Synthesis of β-Branched Tryptophan Analogues Using an Engineered Subunit of Tryptophan Synthase.
Synthesis of β-Branched Tryptophan Analogues Using an Engineered Subunit of Tryptophan Synthase.
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DOI：
10.1021/jacs.6b04836
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发表时间：
2016-07-13
影响因子：
15
通讯作者：
Arnold FH
中科院分区：
文献类型：
--
作者：
Herger M;van Roye P;Romney DK;Brinkmann-Chen S;Buller AR;Arnold FH
我们报道，在激烈火球菌色氨酸合酶工程化亚基的 β 取代反应中，L-苏氨酸可能取代 L-丝氨酸，一步生成 (2S,3S)-β-甲基色氨酸 (β-MeTrp)。通过定向进化，野生型 β 亚基在此底物上的微量活性增强了 1,000 倍以上。结构和光谱数据表明这种增加与亲电子氨基丙烯酸酯中间体的稳定相关。该工程生物催化剂还可与多种吲哚类似物和苯硫酚反应，进行非对映选择性 C-C、C-N 和 C-S 键形成反应。这种新活性绕过了在自然界中产生 β-MeTrp 的 3 酶途径，并为制备这种有价值的结构单元的衍生物提供了一种简单且可扩展的途径。
We report that l-threonine may substitute for l-serine in the β-substitution reaction of an engineered subunit of tryptophan synthase from Pyrococcus furiosus, yielding (2S,3S)-β-methyltryptophan (β-MeTrp) in a single step. The trace activity of the wild-type β-subunit on this substrate was enhanced more than 1,000-fold by directed evolution. Structural and spectroscopic data indicate that this increase is correlated with stabilization of the electrophilic aminoacrylate intermediate. The engineered biocatalyst also reacts with a variety of indole analogs and thiophenol for diastereoselective C-C, C-N, and C-S bond forming reactions. This new activity circumvents the 3-enzyme pathway that produces β-MeTrp in nature and offers a simple and expandable route to preparing derivatives of this valuable building block.