Donor Promiscuity of a Thermostable Transketolase by Directed Evolution: Efficient Complementation of 1-Deoxy-<scp>d</scp>
-xylulose-5-phosphate Synthase Activity
作者:Thangavelu Saravanan、Sebastian Junker、Michael Kickstein、Sascha Hein、Marie-Kristin Link、Jan Ranglack、Samantha Witt、Marion Lorillière、Laurence Hecquet、Wolf-Dieter Fessner
DOI:10.1002/anie.201701169
日期:2017.5.2
Enzymes catalyzing asymmetric carboligation reactions typically show very high substrate specificity for their nucleophilic donor substrate components. Structure‐guided engineering of the thermostable transketolase from Geobacillus stearothermophilus by directed in vitro evolution yielded new enzyme variants that are able to utilize pyruvate and higher aliphatic homologues as nucleophilic components
催化不对称碳连接反应的酶通常对其亲核供体底物组分显示很高的底物特异性。通过定向体外进化对源自嗜热脂肪热地芽孢杆菌的热稳定的转酮醇酶进行结构导向的工程改造,产生了新的酶变体,该变体能够利用丙酮酸和更高的脂肪族同源物作为亲核组分进行酰基转移,而不是天然的多羟基化酮糖磷酸酯或羟基丙酮酸。单个突变体H102T证明对3-甲基-2-氧代丁酸酯作为供体的打击最大,而双突变体H102L / H474S对丙酮酸作为供体则显示出最高的催化效率。后一种变体能够补充大肠杆菌的营养缺陷型dxs基因缺失产生的细胞,该基因编码进入萜类生物合成的第一个重要步骤的活性,从而提供了机会进行生长选择测试以进一步优化酶。