POSSIBLE BINDING MODES FOR DINITROGEN ACTIVATION BY THE FEMO-COFACTORIN NITROGENASE

Dinitrogen activation at the FeMo-cofactor site of nitrogenase was stu died based upon the quantum chemical CNDO calculations performed on po ssible processes of dinitrogen approaching and binding to the FeMo-cof actor. The best dinitrogen binding mode suggested in this article is t he dinitrogen-inserting end-on mode, in which one nitrogen atom is loc ated at the geometrical center of the FeMo-cofactor, and another nitro gen atom keeps out of the Fe-4 surface of the Fe-6 prism of the FeMo-c ofactor. The mechanism of protonation of dinitrogen at the FeMo-cofact or site is discussed based upon the suggested binding mode. Copyright (C) 1996 Elsevier Science Ltd