Specificity of NifEN and VnfEN for the Assembly of Nitrogenase Active Site Cofactors in Azotobacter vinelandii
Ana Pérez‐González, Emilio Jiménez‐Vicente, Jakob Gies‐Elterlein, Alvaro Salinero‐Lanzarote, Zhi‐Yong Yang, Oliver Einsle, Lance C. Seefeldt, Dennis R. Dean
Abstract
Biological nitrogen fixation is a complex process involving the nitrogenases. The biosynthesis of an active nitrogenase involves a large number of genes and the coordinated function of their products. Understanding the details of the assembly and activation of the different nitrogen fixation components, in particular the simplest one known so far, the Fe-only nitrogenase, would contribute to the goal of transferring the necessary genetic elements of bacterial nitrogen fixation to cereal crops to endow them with the capacity for self-fertilization. In this work, we show that there is no need for a scaffold complex for the assembly of the FeFe-cofactor, which provides the active site for Fe-only nitrogenase. These results are in agreement with previously reported genetic reconstruction experiments using a non-nitrogen-fixing microbe. In aggregate, these findings provide a high degree of confidence that the Fe-only system represents the simplest and, therefore, most attractive target for mobilizing nitrogen fixation into plants.