Halliwell Tom, Fisher Karl, Payne Karl A P, Rigby Stephen E J, Leys David
Manchester Institute of Biotechnology, University of Manchester, 131 Princess Street, Manchester M1 7DN, UK.
Future Biomanufacturing Research Hub (FutureBRH), Manchester Institute of Biotechnology, University of Manchester, 131 Princess Street, Manchester M1 7DN, UK.
Microorganisms. 2020 Sep 2;8(9):1344. doi: 10.3390/microorganisms8091344.
Reductive dehalogenases are responsible for the reductive cleavage of carbon-halogen bonds during organohalide respiration. A variety of mechanisms have been proposed for these cobalamin and [4Fe-4S] containing enzymes, including organocobalt, radical, or cobalt-halide adduct based catalysis. The latter was proposed for the oxygen-tolerant cataboli reductive dehalogenase (NpRdhA). Here, we present the first substrate bound NpRdhA crystal structures, confirming a direct cobalt-halogen interaction is established and providing a rationale for substrate preference. Product formation is observed due to X-ray photoreduction. Protein engineering enables rational alteration of substrate preference, providing a future blue print for the application of this and related enzymes in bioremediation.
还原脱卤酶负责在有机卤化物呼吸过程中碳-卤键的还原裂解。对于这些含钴胺素和[4Fe-4S]的酶，已经提出了多种机制，包括基于有机钴、自由基或钴-卤化物加合物的催化作用。后者是针对耐氧的分解代谢还原脱卤酶（NpRdhA）提出的。在这里，我们展示了首个结合底物的NpRdhA晶体结构，证实了直接的钴-卤相互作用的建立，并为底物偏好提供了理论依据。由于X射线光还原作用，观察到了产物的形成。蛋白质工程能够合理改变底物偏好，为这种及相关酶在生物修复中的应用提供了未来蓝图。
