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Nickel–Iron–Sulfur Active Sites: Hydrogenase and Co Dehydrogenase

1999; Elsevier BV; Linguagem: Inglês

10.1016/s0898-8838(08)60081-1

1557-8917

Juan C. Fontecilla‐Camps, Stephen W. Ragsdale,

Metal-Catalyzed Oxygenation Mechanisms

This chapter focuses on the proteins that contain both nickel and iron. The chapter provides a list of the three known proteins of this class and the reactions that they catalyze. The active sites of all of these consist of heterometallic nickel–iron–sulfur (NiFeS) clusters. The biologically uncommon Ni center associated with FeS clusters is a powerful and unique catalytic unity. The chapter reviews the structural and mechanistic aspects of three NiFeS centers: the active site of hydrogenase and clusters A and C of CODH/ACS. In the former, the association of a Ni center with the most unusual FeCOC-2 unit is a fascinating one. Model chemists, spectroscopists, and crystallographers have joined efforts to elucidate the reaction mechanism. Although a consensus is being slowly reached, the exact roles of the different active site components have not yet been fully established. Ni appears to be the catalytic center proper, whereas the unusual Fe center may be specially suited to bind a hydride and help electron transfer from it to the FeS clusters and the redox partners.