Formation and characterization of a transition state complex of Azotobacter vinelandii nitrogenase.

A stable complex is formed between the nitrogenase proteins of Azotobacter vinelandii, aluminium fluoride and MgADP. All nitrogenase activities are inhibited. The complex formation was found to be reversible. An incubation at 50 degrees C recovers nitrogenase activity. The complex has been characterized with respect to protein and nucleotide composition and redox state of the metal-sulfur clusters. Based on the inhibition by aluminium fluoride together with MgADP, it is proposed that a stable transition state complex with nitrogenase is isolated.