Identification of nitrogenase cofactor biosynthetic precursors on NifB

The CBGP “Biochemistry of Nitrogen Fixation” group identifies initial FeMo-co precursors and elucidate crucial steps of NifB reaction mechanism.


CBGP researchers, in collaboration with the group of David Britt at the University of California-Davis, show that the nitrogenase iron-molybdenum cofactor (FeMo-co) maturase NifB carries three [4Fe-4S] clusters. In addition to the catalytic SAM binding cluster, NifB carries two auxiliary [4Fe-4S] clusters proposed to serve as substrates for the biosynthesis of the Fe8S9C core of FeMo-co. Spectroscopic evidence indicates coordination of a SAM molecule (acting as methyl donor) to one of the auxiliary clusters, as well as N coordination to at least one of the auxiliary clusters, which permits a mechanism to release the FeS cluster product through protonation. This analysis represents concise and novel data to understand the mechanism of synthesis of the Fe8S9C core of FeMo-co.



Original Paper:

Wilcoxen, J; Arragain, S; Scandurra, AA; Jimenez-Vicente, E; Echavarri-Erasun, C; Pollmann, S; Britt, RD; Rubio, LM. 2016. "Electron paramagnetic resonance characterization of three iron–sulfur clusters present in the nitrogenase cofactor maturase NifB from Methanocaldococcus infernus". Journal of the American Chemical Society. DOI: 10.1021/jacs.6b03329".