Douglas C. Rees (Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena): "The isolation by V.K. Shah and W. Brill (Proceedings of the National Academy of Sciences, 74:3248, 1977) of a low- molecular-weight iron- and molybdenum-containing component from nitrogenase, the FeMo cofactor, catalyzed extensive efforts to structurally characterize the active center of the enzyme responsible for biological nitrogen fixation. Interest in the nitrogenase mechanism was already heightened by the contrast between the mild conditions associated with biological conversion of dinitrogen to ammonia and the high temperature and pressure conditions required for the industrial Haber- Basch process; the report by Shah and Brill provided a convenient approach to directly study the enzyme's active center. Spectroscopic, synthetic, and analytical studies defined many pieces of the structural jigsaw puzzle of the FeMo cofactor, but final assembly of these pieces into the completed structure proved elusive.
"Our involvement in this puzzle resulted ...
