研究通過重塑結合位點使腈水解酶催化的二腈不對稱水解反應發生手性翻轉
作者:
小柯機器人發布時間:2020/11/5 16:09:34
中國科學院天津工業生物技術研究所的朱敦明研究團隊,通過重塑結合位點使腈水解酶催化的二腈不對稱水解反應發生手性翻轉。 該項研究成果發表在2020年11月3日的《德國應用化學》上。
在這項研究中,通過採用「鏡像」策略,即對底物結合口袋進行對稱性分析,研究人員在來自集胞藻PCC6803的腈水解酶中,發現了兩個關鍵的影響3-異丁基戊二腈水解手性選擇性的胺基酸殘基,即W170和V198。將這兩個胺基酸殘基互換導致手性選擇性發生翻轉(由S, 90% ee變為R, 47% ee)。通過常規的點飽和突變和組合突變,研究人員進一步重塑了底物結合口袋,獲得了具有更高活性和手性選擇性(R, 99% ee)的突變體E8。該突變型的酶被用於製備光學純的(R)-3-異丁基-4-氰基丁酸,並在一系列3-取代的戊二腈水解反應中表現出類似的手性選擇性翻轉。
這項研究為翻轉腈水解酶及其他酶催化含兩個相同反應基團的前手性底物的不對稱反應的光學選擇性提供了一個通用的策略,在不對稱合成中這種策略是急需的。
據了解,腈水解酶催化的前手性二腈的不對稱水解是一種有吸引力的合成手性氰基羧酸——一種用於合成製藥工業中重要的γ-胺基酸的前體——的方法。然而,已經測試過的腈水解酶在催化3-烷基或芳基取代的戊二腈時主要生成(S)-構象的氰基羧酸。
附:英文原文
Title: Inverting the enantiopreference of nitrilase‐catalyzed desymmetric hydrolysis of prochiral dinitriles by reshaping the binding pocket with a 「mirror‐image」 strategy
Author: Shanshan Yu, Jinlong Li, Peiyuan Yao, Jinhui Feng, Yunfeng Cui, Jianjiong Li, Xiangtao Liu, Qiaqing Wu, Jianping Lin, Dunming Zhu
Issue&Volume:03 November 2020
Abstract: Nitrilase‐catalyzed desymmetric hydrolysis of prochiral dinitriles is an attractive method for the synthesis of chiral cyanocarboxylic acids, the precursors to pharmaceutically important γ‐amino acids. However, the tested nitrilases towards 3‐alkyl‐ or aryl substituted glutaronitriles mostly generate ( S )‐configurated cyanocarboxylic acids. Herein a 「mirror‐image」 strategy, i.e. symmetry analysis of substrate‐binding pocket, was applied to identify two key amino acid residues W170 and V198 that possibly modulate the enantiopreference of a nitrilase from Synechocystis sp. PCC6803 towards 3‐isobutyl glutaronitrile ( 1a ). Exchange of these two residues resulted in the enantiopreference inversion ( S , 90% ee to R , 47% ee ). By further reshaping the substrate‐binding pocket via routine site‐saturation and combinatorial mutagenesis, variant E8 with higher activity and stereoselectivity (99% ee , R ) was obtained. The mutant enzyme was applied in the preparation of optically pure ( R )‐3‐isobutyl‐4‐cyanobutanoic acid (( R )‐ 2a ), and showed similar stereopreference inversion towards a series of 3‐substituted glutaronitriles. This study may offer a general strategy to switch the stereopreference of other nitrilases and other classes of enzymes toward the desymmetric reactions of prochiral substrates with two identical reactive functional groups, that are often desirable in asymmetric synthesis.
DOI: 10.1002/anie.202012243
Source: https://onlinelibrary.wiley.com/doi/10.1002/anie.202012243