Fig. 1.
Ball-and-stick representation of the nitrogenase metalloclusters. Shown are the Fe-protein [4Fe:4S] cluster (A) and the two clusters of the MoFe protein, FeMo cofactor, and the P cluster (B) assigned to the oxidation state PN (C). The radii of all non-protein atoms have been set to 0.7 Å, and the protein ligands are presented as black bonds. Iron, molybdenum, sulfur, carbon, oxygen, and nitrogen atoms are colored burgundy, orange, yellow, gray, red, and blue, respectively. This figure was generated with the program MolScript (74) from Protein Data Bank entries 2NIP, 1M1N, and 3MIN.