Precision is essential for efficient catalysis in an evolved Kemp eliminase
Precision is essential for efficient catalysis in an evolved Kemp eliminase
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DOI：
10.1038/nature12623
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发表时间：
2013-11-21
期刊：
影响因子：
64.8
通讯作者：
Hilvert, Donald
中科院分区：
文献类型：
--
作者：
Blomberg, Rebecca;Kries, Hajo;Hilvert, Donald
莱纳斯·鲍林 (Linus Pauling) 在六十多年前建立了理解和模拟酶的概念框架(1)。酶选择性地稳定相对于结合基态的催化反应的限速过渡态这一概念将设计问题简化为分子识别问题之一。然而，过去利用这一想法的尝试，例如通过使用过渡态类似物来引发具有催化活性的抗体(2)，通常未能提供真正的酶促速率。计算设计方法的出现与定向进化相结合，为重新审视这个问题提供了机会。从计算设计的 Kemp 消除催化剂（3）（一种经过充分研究的碳质子转移模型系统）开始，我们证明可以进化出一种人工酶，将基本化学反应加速 6 x 10(8) 倍，接近高度优化的天然酶（如磷酸丙糖异构酶）的卓越效率。进化酶的1.09埃分辨率晶体结构表明，可以成功地利用熟悉的催化策略（例如形状互补和精确放置的催化基团）来提供如此高的速率加速，这使我们对设计更复杂的催化剂的前景感到乐观。
Linus Pauling established the conceptual framework for understanding and mimicking enzymes more than six decades ago(1). The notion that enzymes selectively stabilize the rate-limiting transition state of the catalysed reaction relative to the bound ground state reduces the problem of design to one of molecular recognition. Nevertheless, past attempts to capitalize on this idea, for example by using transition state analogues to elicit antibodies with catalytic activities(2), have generally failed to deliver true enzymatic rates. The advent of computational design approaches, combined with directed evolution, has provided an opportunity to revisit this problem. Starting from a computationally designed catalyst for the Kemp elimination(3)-a well-studied model system for proton transfer from carbon-we show that an artificial enzyme can be evolved that accelerates an elementary chemical reaction 6 x 10(8)-fold, approaching the exceptional efficiency of highly optimized natural enzymes such as triosephosphate isomerase. A 1.09 angstrom resolution crystal structure of the evolved enzyme indicates that familiar catalytic strategies such as shape complementarity and precisely placed catalytic groups can be successfully harnessed to afford such high rate accelerations, making us optimistic about the prospects of designing more sophisticated catalysts.