Chromobacterium violaceum ω-transaminase variant Trp60Cys shows increased specificity for (S)-1-phenylethylamine and 4′-substituted acetophenones, and follows Swain-Lupton parameterisation
Chromobacterium violaceum ω-transaminase variant Trp60Cys shows increased specificity for (S)-1-phenylethylamine and 4′-substituted acetophenones, and follows Swain-Lupton parameterisation
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DOI：
10.1039/c2ob25893e
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发表时间：
2012-01-01
影响因子：
3.2
通讯作者：
Berglund, Per
中科院分区：
文献类型：
--
作者：
Cassimjee, Karim Engelmark;Humble, Maria Svedendahl;Berglund, Per
对于生物催化生产药学上重要的手性胺，转氨酶已被证明是有用的。这些酶的工程化在一定程度上是通过合理设计完成的，但主要是通过定向进化。通过使用同源性模型，在与来自同源酶的工程化变体比较后发现紫色色杆菌ω-转氨酶中的关键点突变。变体Trp 60 Cys对（S）-1-苯乙胺（29倍）和4 '-取代苯乙酮（类似于5倍）的特异性增加。为了进一步研究突变的影响，对反应速率进行了Swain-Lupton参数化。与野生型相比，反应的变体显示增加共振依赖性，这一观察结果与改变pH值的最佳和辅因子的依赖性表明一个改变的反应机制。
For biocatalytic production of pharmaceutically important chiral amines the.-transaminase enzymes have proven useful. Engineering of these enzymes has to some extent been accomplished by rational design, but mostly by directed evolution. By use of a homology model a key point mutation in Chromobacterium violaceum omega-transaminase was found upon comparison with engineered variants from homologous enzymes. The variant Trp60Cys gave increased specificity for (S)-1-phenylethylamine (29-fold) and 4'-substituted acetophenones (similar to 5-fold). To further study the effect of the mutation the reaction rates were Swain-Lupton parameterised. On comparison with the wild type, reactions of the variant showed increased resonance dependence; this observation together with changed pH optimum and cofactor dependence suggests an altered reaction mechanism.