Synthetic models of the nitrogenase FeMo cofactor
Abstract
The FeMo cofactor (FeMoco), the key active site in the Mo-based nitrogenase, is one of the most complicated metalloenzyme molecules. Synthesis of the FeMoco model cluster ([MoFe 7 S 9 C]) is essential to understanding its function in dinitrogen binding, activation, and conversion. However, the complex framework of the FeMoco cluster, which features a unique trigonal prismatic [Fe 6 C] moiety comprising a µ 6 -bridging carbide, has made the synthesis of the cluster a persistent challenge. In this work, two analogous mimics of FeMoco have been synthesized, using a cluster-coupling synthetic strategy facilitated by the fabrication of unsaturated ligand/metal coordination. The incorporation of a µ 6 -X (X = C 4− or N 3− ) to construct the characteristic triangular prismatic [Fe 6 ( µ 6 -X)] moiety, replicating that in FeMoco, has been achieved synthetically. The two mimics have similar key structural parameters to FeMoco in natural nitrogenase, but differ from the FeMoco structure in two major aspects: the µ 2 -bridging ligands and the metal atoms capping the [Fe 6 S 9 C] cores (Mo/Fe in FeMoco vs. Mo/Mo or W/W in the synthetic models). Quantum chemical studies indicate that the electronic ground states of these clusters resemble those observed for FeMoco, with maximized antiferromagnetic coupling among the iron centers. A future systematic study on the physical and chemical properties of a family of mimics with programmed variations of key structural elements can provide a valuable comparison and facilitate a better understanding of the structure and function of FeMoco.
Article Details
Journal Info
Proceedings of the National Academy of Sciences
National Academy of Sciences
Authors (17)
Yun-Yu Xu
State Key Laboratory of Microbial Technology, Jiangsu Collaborative Innovation Center of Biomedical Functional Materials, School of Chemistry and Materials Science, Nanjing Normal University
Xue-Lian Jiang
Department of Chemistry and Engineering Research Center of Advanced Rare-Earth Materials of Ministry of Education
Jia-Lu Chai
State Key Laboratory of Microbial Technology, Jiangsu Collaborative Innovation Center of Biomedical Functional Materials, School of Chemistry and Materials Science, Nanjing Normal University
Shu-Juan Qiu
State Key Laboratory of Microbial Technology, Jiangsu Collaborative Innovation Center of Biomedical Functional Materials, School of Chemistry and Materials Science, Nanjing Normal University
Juan He
State Key Laboratory of Microbial Technology, Jiangsu Collaborative Innovation Center of Biomedical Functional Materials, School of Chemistry and Materials Science, Nanjing Normal University
Gan Xu
Department of Chemistry, State Key Laboratory of Marine Pollution
Jia Wei
State Key Laboratory of Microbial Technology, Jiangsu Collaborative Innovation Center of Biomedical Functional Materials, School of Chemistry and Materials Science, Nanjing Normal University
Qiu-Xiang Yu
State Key Laboratory of Microbial Technology, Jiangsu Collaborative Innovation Center of Biomedical Functional Materials, School of Chemistry and Materials Science, Nanjing Normal University
Hong-Ying Zhang
State Key Laboratory of Microbial Technology, Jiangsu Collaborative Innovation Center of Biomedical Functional Materials, School of Chemistry and Materials Science, Nanjing Normal University
Yue Li
Xiao-Wen Zhang
Department of Chemistry, Brandeis University, 415 South Street, Waltham, Massachusetts 02453, United States
Guo-Liang Cao
State Key Laboratory of Microbial Technology, Jiangsu Collaborative Innovation Center of Biomedical Functional Materials, School of Chemistry and Materials Science, Nanjing Normal University
Yong Li
Yun-Shu Cui
Department of Chemistry
Cong-Qiao Xu
Department of Chemistry and Guangdong Provincial Key Laboratory of Catalytic Chemistry, Southern University of Science and Technology
Jun Li
Xu-Dong Chen
State Key Laboratory of Microbial Technology, Jiangsu Collaborative Innovation Center of Biomedical Functional Materials, School of Chemistry and Materials Science, Nanjing Normal University