From the reduction of dinitrogen to the oxidation of water, the chemical transformations catalysed by metalloenzymes underlie global geochemical and biochemical cycles. These reactions represent some of the most kinetically and thermodynamically challenging processes known and require the complex choreography of the fundamental building blocks of nature, electrons and protons, to be carried out with utmost precision and accuracy. The rate-determining step of catalysis in many metalloenzymes consists of a protein structural rearrangement, suggesting that nature has evolved to leverage macroscopic changes in protein molecular structure to control subatomic changes in metallocofactor electronic structure. The proton-coupled electron transfer mechanisms operative in nitrogenase, photosystem II and ribonucleotide reductase exemplify this interplay between molecular and electronic structural control. We present the culmination of decades of study on each of these systems and clarify what is known regarding the interplay between structural changes and functional outcomes in these metalloenzyme linchpins.

从二氮的还原到水的氧化，金属酶催化的化学转化是全球地球化学和生化循环的基础。这些反应代表了一些已知的最具动力学和热力学挑战性的过程，需要对自然界的基本组成部分——电子和质子——进行复杂的编排，以最高的精度和准确性进行。许多金属酶中催化的速率决定步骤包括蛋白质结构重排，这表明自然界已经进化为利用蛋白质分子结构的宏观变化来控制金属因子电子结构的亚原子变化。在固氮酶、光系统 II 和核糖核苷酸还原酶中起作用的质子耦合电子转移机制体现了分子和电子结构控制之间的这种相互作用。我们介绍了对这些系统中每个系统数十年研究的成果，并阐明了关于这些金属酶关键结构变化和功能结果之间相互作用的已知信息。