Institute for Molecules and Materials, Radboud University Nijmegen, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands.
J Am Chem Soc. 2021 Apr 21;143(15):5709-5716. doi: 10.1021/jacs.0c12956. Epub 2021 Apr 12.
Ultrasensitivity is a ubiquitous emergent property of biochemical reaction networks. The design and construction of synthetic reaction networks exhibiting ultrasensitivity has been challenging, but would greatly expand the potential properties of life-like materials. Herein, we exploit a general and modular strategy to reversibly regulate the activity of enzymes using light and show how ultrasensitivity arises in simple out-of-equilibrium enzymatic systems upon incorporation of reversible photoswitchable inhibitors (PIs). Utilizing a chromophore/warhead strategy, PIs of the protease α-chymotrypsin were synthesized, which led to the discovery of inhibitors with large differences in inhibition constants () for the different photoisomers. A microfluidic flow setup was used to study enzymatic reactions under out-of-equilibrium conditions by continuous addition and removal of reagents. Upon irradiation of the continuously stirred tank reactor with different light pulse sequences, i.e., varying the pulse duration or frequency of UV and blue light irradiation, reversible switching between photoisomers resulted in ultrasensitive responses in enzymatic activity as well as frequency filtering of input signals. This general and modular strategy enables reversible and tunable control over the kinetic rates of individual enzyme-catalyzed reactions and makes a programmable linkage of enzymes to a wide range of network topologies feasible.
超敏性是生化反应网络普遍存在的突现属性。设计和构建表现出超敏性的合成反应网络具有挑战性，但将极大地扩展类生命材料的潜在特性。在此，我们利用一种通用的模块化策略，使用光来可逆地调节酶的活性，并展示在简单的非平衡酶系统中，当加入可逆的光致开关抑制剂（PIs）时，超敏性是如何产生的。利用生色团/弹头策略，合成了蛋白酶 α-糜蛋白酶的 PIs，这导致发现了对不同光异构体的抑制常数（）有很大差异的抑制剂。微流控流动装置用于通过连续添加和去除试剂在非平衡条件下研究酶反应。通过用不同的光脉冲序列辐照连续搅拌釜反应器，即改变紫外光和蓝光辐照的脉冲持续时间或频率，光异构体的可逆切换导致酶活性的超敏响应以及输入信号的频率滤波。这种通用的模块化策略能够对单个酶催化反应的动力学速率进行可逆和可调的控制，并使酶与广泛的网络拓扑结构的可编程连接成为可能。
