A BAHD terpene alcohol acyltransferase, CaAT20, was identified from Celastrus angulatus Maxim, expressed in E. coli and functionally characterized. S405A mutant of CaAT20 increased the enzyme activity. Acylation is a diversely physiological process in the biosynthesis of plant secondary metabolites. Plant BAHD acyltransferases play an important role in the modification of volatile esters with biological activities. In this research, a BAHD acyltransferase (CaAT20) was identified from Celastrus angulatus Maxim and the function of this enzyme was characterized. CaAT20 could convert geraniol to geranyl esters by using benzoyl-CoA and acetyl-CoA as the acyl donors respectively. Furthermore, the catalytic activity of CaAT20 for benzoyl-CoA was higher than that of acetyl-CoA. Site-directed mutation of CaAT20 was carried out based on the results of molecular simulation. In vitro site-directed mutant S405A of CaAT20 increased the volume of binding cavity so as to facilitate the entry of geraniol, indicating a more efficient acylation for geraniol and benzoyl-CoA. Our research provides new insight for the catalytic functions of CaAT20.

中文翻译：

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尖竹桃 BAHD 酰基转移酶的功能表征和催化活性改进

从 Celastrus angulatus Maxim 中鉴定出一种 BAHD 萜烯醇酰基转移酶 CaAT20，在大肠杆菌中表达并对其进行功能表征。CaAT20 的 S405A 突变体增加了酶活性。酰化是植物次生代谢物生物合成中的多种生理过程。植物BAHD酰基转移酶在具有生物活性的挥发性酯的修饰中起重要作用。在这项研究中，从 Celastrus angulatus Maxim 中鉴定出一种 BAHD 酰基转移酶 (CaAT20)，并对该酶的功能进行了表征。CaAT20可以分别以苯甲酰辅酶A和乙酰辅酶A作为酰基供体，将香叶醇转化为香叶酯。此外，CaAT20对苯甲酰辅酶A的催化活性高于乙酰辅酶A。基于分子模拟的结果进行CaAT20的定点突变。CaAT20的体外定点突变体S405A增加了结合腔的体积以促进香叶醇的进入，表明香叶醇和苯甲酰辅酶A的酰化更有效。我们的研究为 CaAT20 的催化功能提供了新的见解。