STRUCTURE AND ENVIRONMENT OF METAL-CLUSTERS IN THE NITROGENASE MOLYBDENUM IRON PROTEIN FROM CLOSTRIDIUM-PASTEURIANUM

The MoFe protein of Mo-dependent nitrogenases binds large and unusual metal-sulfur clusters of two types. These clusters are believed to be involved in the catalytic reduction of dinitrogen to ammonia by the enzyme. An analysis, atomic models for the MoFe protein from Clostridium pasteurianum at 2.2 angstrom resolution is underway. On the basis of this analysis, atomic models for the structure of the FeMo cofactor and the Fe8S8 cluster, the interactions of these clusters with the protein, and general features of the protein structure are described. Two possible through-bond paths for electron transfer the two clusters are identified.