Molecular biology achieves control over complex reaction networks by means of molecular systems that translate a chemical input (such as ligand binding) into an orthogonal chemical output (such as acylation or phosphorylation). We present an artificial molecular translation device that converts a chemical input – the presence of chloride ions – into an unrelated chemical output: modulation of the reactivity of an imidazole moiety, both as a Brønsted base and as a nucleophile. The modulation of reactivity operates through the allosteric remote control of imidazole tautomer states. The reversible coordination of chloride to a urea binding site triggers a cascade of conformational changes in a chain of ethylene-bridged hydrogen-bonded ureas, switching the chain’s global polarity, that in turn modulates the tautomeric equilibrium of a distal imidazole, and hence its reactivity. Switching reactivities of active sites by dynamically controlling their tautomer states is an untapped strategy for building functional molecular devices with allosteric enzyme-like properties.

分子生物学通过分子系统将化学输入（如配体结合）转化为正交化学输出（如酰化或磷酸化）来实现对复杂反应网络的控制。我们提出了一种人工分子翻译装置，可将化学输入（氯离子的存在）转化为无关的化学输出：调节咪唑部分的反应性，既可以作为 Brønsted 碱，也可以作为亲核试剂。反应性的调节通过咪唑互变异构体状态的变构远程控制来运作。氯化物与尿素结合位点的可逆配位触发了亚乙基氢键尿素链中的一连串构象变化，从而改变了链的全局极性，进而调节远端咪唑的互变异体平衡，从而调节其反应性。通过动态控制活性位点的互变异构体状态来切换活性位点的反应性是构建具有变构酶样特性的功能性分子装置的一种尚未开发的策略。