Artificial transfer hydrogenases based on the biotin-(strept)avidin technology: Fine tuning the selectivity by saturation mutagenesis of the host protein
Artificial transfer hydrogenases based on the biotin-(strept)avidin technology: Fine tuning the selectivity by saturation mutagenesis of the host protein
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DOI：
10.1021/ja061580o
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发表时间：
2006-06-28
影响因子：
15
通讯作者：
Ward, Thomas R.
中科院分区：
文献类型：
--
作者：
Letondor, Christophe;Pordea, Anca;Ward, Thomas R.
在链霉亲和素中加入生物素化的外消旋三足d(6)-钢琴凳复合物，产生对映选择性转移氢化人工金属酶，用于酮的还原。在确定了野生型链霉亲和素存在的最有前途的有机金属催化剂前体后，通过S112位置的饱和诱变实现了选择性的微调。这种遗传优化位点的选择是由对接研究提出的，该研究表明，该位置最接近生物素化的金属，当与链霉亲和素结合时。对于芳香酮，反应顺利进行，生成相应的对映体富集醇，其ee (R)可达97%或70%。基于这些结果，我们认为对映体选择主要是由底物和eta(6)结合芳烃之间的CH/pi相互作用决定的。然而，在S112位置存在阳离子残基时，这些对映体辨别相互作用可以被抵消，从而产生相反的产物对映体。
Incorporation of biotinylated racemic three-legged d(6)-piano stool complexes in streptavidin yields enantioselective transfer hydrogenation artificial metalloenzymes for the reduction of ketones. Having identified the most promising organometallic catalyst precursors in the presence of wild-type streptavidin, fine-tuning of the selectivity is achieved by saturation mutagenesis at position S112. This choice for the genetic optimization site is suggested by docking studies which reveal that this position lies closest to the biotinylated metal upon incorporation into streptavidin. For aromatic ketones, the reaction proceeds smoothly to afford the corresponding enantioenriched alcohols in up to 97% ee (R) or 70% (S). On the basis of these results, we suggest that the enantioselection is mostly dictated by CH/pi interactions between the substrate and the eta(6)-bound arene. However, these enantiodiscriminating interactions can be outweighed in the presence of cationic residues at position S112 to afford the opposite enantiomers of the product.