Mutations affecting the internal equilibrium of the reaction catalyzed by 6-aminohexanoate-dimer hydrolase
Mutations affecting the internal equilibrium of the reaction catalyzed by 6-aminohexanoate-dimer hydrolase
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影响 6-氨基己酸二聚体水解酶催化反应内部平衡的突变
DOI：
10.1002/1873-3468.12354
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发表时间：
2016
期刊：
影响因子：
3.5
通讯作者：
Higuchi Y
中科院分区：
文献类型：
--
作者：
Negoro S;Kawashima Y;Shibata N;Kobayashi T;Baba T;Lee YH;Kamiya K;Shigeta Y;Nagai K;Takehara I;Kato D;Takeo M;Higuchi Y
6 -氨基己酸二聚体水解酶催化酰胺合成。当使用位于催化裂口入口处的几个氨基酸取代的酶突变体时，发现在90%的t -丁醇中该逆反应的产率发生了巨大变化。环区的移动和Tyr170的翻转在酶的催化中心产生局部疏水环境。在这里，我们提出，“水排除效应”改变了酶-底物复合物和酶-产物复合物之间的内部平衡，改变了正向和反向反应的速率。此外，我们认为局部疏水环境可能提供一个适合于高效酰胺合成的反应中心。DatabasePDB代码3VWL: Hyb‐24DNY‐S187PDB代码3VWM: Hyb‐24DNY‐A187PDB代码3VWN: Hyb‐24DNY‐G187PDB代码3A65: Hyb‐24DN‐A112/Ahx complexPDB代码3A66: Hyb‐24DNY‐S187A112/Ahx complexPDB代码3VWP: Hyb‐24DNY‐S187A112/Ahx complexPDB代码3VWQ: Hyb‐24DNY‐A187A112/Ahx complexPDB代码3VWR: Hyb‐24DNY‐A187A112/Ahx complexPDB代码3VWR: Hyb‐24DNY‐A187A112/Ahx complexPDB代码3VWR: Hyb‐24DNY‐G187A112/Ahx complex
The enzyme 6‐aminohexanoate‐dimer hydrolase catalyzes amide synthesis. The yield of this reverse reaction in 90%t‐butyl alcohol was found to vary drastically when enzyme mutants with substitutions of several amino acids located at the entrance of the catalytic cleft were used. Movement of the loop region and the flip‐flop of Tyr170 generate a local hydrophobic environment at the catalytic center of the enzyme. Here, we propose that the shift of the internal equilibrium between the enzyme–substrate complex and enzyme–product complex by the ‘water‐excluding effect’ alters the rate of the forward and reverse reactions. Moreover, we suggest that the local hydrophobic environment potentially provides a reaction center suitable for efficient amide synthesis.DatabasePDB code 3VWL: Hyb‐24DNY‐S187PDB code 3VWM: Hyb‐24DNY‐A187PDB code 3VWN: Hyb‐24DNY‐G187PDB code 3A65: Hyb‐24DN‐A112/Ahx complexPDB code 3A66: Hyb‐24DNY‐A112/Ahx complexPDB code 3VWP: Hyb‐24DNY‐S187A112/Ahx complexPDB code 3VWQ: Hyb‐24DNY‐A187A112/Ahx complexPDB code 3VWR: Hyb‐24DNY‐G187A112/Ahx complex