PDF(Pubmed)
Abstract：
Genetic code expansion has emerged as a powerful tool for precisely introducing unnatural chemical structures into proteins to improve their catalytic functions. Given the high catalytic propensity of histidine in the enzyme pocket, increasing the chemical diversity of catalytic histidine could result in new characteristics of biocatalysts. Herein, we report the genetically encoded Nδ-Vinyl Histidine (δVin-H) and achieve the wild-type-like incorporation efficiency by the evolution of pyrrolysyl tRNA synthetase. As histidine usually acts as the nucleophile or the metal ligand in the catalytic center, we replace these two types of catalytic histidine to δVin-H to improve the performance of the histidine-involved catalytic center. Additionally, we further demonstrate the improvements of the hydrolysis activity of a previously reported organocatalytic esterase (the OE1.3 variant) in the acidic condition and myoglobin (Mb) catalyzed carbene transfer reactions under the aerobic condition. As histidine is one of the most frequently used residues in the enzyme catalytic center, the derivatization of the catalytic histidine by δVin-H holds a great potential to promote the performance of biocatalysts.
摘要：
遗传密码扩展已成为将非天然化学结构精确引入蛋白质以改善其催化功能的强大工具。鉴于组氨酸在酶袋中的高催化倾向，增加催化组氨酸的化学多样性可能导致生物催化剂的新特性。在这里，我们报告了遗传编码的Nδ-乙烯基组氨酸（δVin-H），并通过吡咯赖氨酰tRNA合成酶的进化实现了野生型样掺入效率。由于组氨酸通常在催化中心充当亲核试剂或金属配体，我们将这两种类型的催化组氨酸替换为δVin-H，以提高组氨酸参与的催化中心的性能。此外,我们进一步证明了先前报道的有机催化酯酶（OE1.3变体）在酸性条件下的水解活性和在有氧条件下的肌红蛋白（Mb）催化的卡宾转移反应的改善。由于组氨酸是酶催化中心中最常用的残基之一，催化组氨酸通过δVin-H的衍生具有促进生物催化剂性能的巨大潜力。
