Crystallographic Analysis of the Mofe Protein of Nitrogenase from a Nifv Mutant of Klebsiella Pneumoniae Identifies Citrate as a Ligand to the Molybdenum of Iron Molybdenum Cofactor (Femoco).
Mayer, S.M., Gormal, C.A., Smith, B.E., Lawson, D.M.(2002) J Biol Chem 277: 35263
- PubMed: 12133839 
- DOI: https://doi.org/10.1074/jbc.M205888200
- Primary Citation of Related Structures:  
1H1L - PubMed Abstract: 
The x-ray crystal structure of NifV(-) Klebsiella pneumoniae nitrogenase MoFe protein (NifV(-) Kp1) has been determined and refined to a resolution of 1.9 A. This is the first structure for a nitrogenase MoFe protein with an altered cofactor. Moreover, it is the first direct evidence that the organic acid citrate is not just present, but replaces homocitrate as a ligand to the molybdenum atom of the iron molybdenum cofactor (FeMoco). Subsequent refinement of the structure revealed that the citrate was present at reduced occupancy.
Organizational Affiliation: 
Department of Biological Chemistry, John Innes Centre, Norwich NR4 7UH, United Kingdom.