近日，美国加州大学圣迭戈分校F. Akif Tezcan、Mark A.HerzikJr.等研究人员合作揭示在催化周转条件下制备的固氮酶复合物结构。该项研究成果于2022年7月28日在线发表在《科学》杂志上。

研究人员报告了在酶周转条件下制备的固氮酶复合物的冷冻电镜结构。研究人员观察到，不对称性制约着固氮酶机制的所有方面，包括三磷酸腺苷（ATP）水解、蛋白-蛋白相互作用和催化作用。催化铁钼辅因子附近的构型变化与酶的核苷酸水解状态相关联。

据介绍，固氮酶将ATP水解与大气中二氮的多电子还原成氨结合起来。尽管进行了广泛的研究，但人们对依赖ATP的能量转导和氮气还原的机制细节还不是很了解，需要有新的策略来监测其催化作用期间的结构动态。

附：英文原文

Title: Structures of the nitrogenase complex prepared under catalytic turnover conditions

Author: Hannah L. Rutledge, Brian D. Cook, Hoang P. M. Nguyen, Mark A. HerzikJr., F. Akif Tezcan

Issue&Volume: 2022-07-28

Abstract: The enzyme nitrogenase couples adenosine triphosphate (ATP) hydrolysis to the multi-electron reduction of atmospheric dinitrogen into ammonia. Despite extensive research, the mechanistic details of ATP-dependent energy transduction and dinitrogen reduction by nitrogenase are not well understood, requiring new strategies to monitor its structural dynamics during catalytic action. Here we report cryogenic electron microscopy structures of the nitrogenase complex prepared under enzymatic turnover conditions. We observe that asymmetry governs all aspects of nitrogenase mechanism including ATP hydrolysis, protein-protein interactions, and catalysis. Conformational changes near the catalytic iron-molybdenum cofactor are correlated with the nucleotide-hydrolysis state of the enzyme.

DOI: abq7641

Source: https://www.science.org/doi/10.1126/science.abq7641