School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), 50 UNIST-gil, Ulsan, 44919, Republic of Korea.
Department of Chemistry, College of Natural Sciences, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea.
Nat Commun. 2024 Mar 28;15(1):2732. doi: 10.1038/s41467-024-46909-1.
Fe‒S cluster-harboring enzymes, such as carbon monoxide dehydrogenases (CODH), employ sophisticated artificial electron mediators like viologens to serve as potent biocatalysts capable of cleaning-up industrial off-gases at stunning reaction rates. Unraveling the interplay between these enzymes and their associated mediators is essential for improving the efficiency of CODHs. Here we show the electron mediator-interaction site on ChCODHs (Ch, Carboxydothermus hydrogenoformans) using a systematic approach that leverages the viologen-reactive characteristics of superficial aromatic residues. By enhancing mediator-interaction (R57G/N59L) near the D-cluster, the strategically tailored variants exhibit a ten-fold increase in ethyl viologen affinity relative to the wild-type without sacrificing the turn-over rate (k). Viologen-complexed structures reveal the pivotal positions of surface phenylalanine residues, serving as external conduits for the D-cluster to/from viologen. One variant (R57G/N59L/A559W) can treat a broad spectrum of waste gases (from steel-process and plastic-gasification) containing O. Decoding mediator interactions will facilitate the development of industrially high-efficient biocatalysts encompassing gas-utilizing enzymes.
含铁-硫簇酶，如一氧化碳脱氢酶（CODH），采用复杂的人工电子介体，如联吡啶，作为强大的生物催化剂，能够以惊人的反应速率清除工业废气。揭示这些酶与其相关介体之间的相互作用对于提高 CODH 的效率至关重要。在这里，我们使用一种系统的方法来展示 ChCODHs（Ch，Carboxydothermus hydrogenoformans）上的电子介体相互作用位点，该方法利用了表面芳香残基对联吡啶的反应特性。通过增强 D 簇附近的介体相互作用（R57G/N59L），经过策略性设计的变体与野生型相比，对乙基联吡啶的亲和力增加了十倍，而不会牺牲周转率（k）。联吡啶络合物的结构揭示了表面苯丙氨酸残基的关键位置，它们作为 D 簇与联吡啶之间的外部通道。一个变体（R57G/N59L/A559W）可以处理含有 O 的多种废气（来自钢铁加工和塑料气化）。解析介体相互作用将有助于开发包括利用气体的酶在内的工业高效生物催化剂。
