title: Characterization of the active site of catalytically inactive forms of [NiFe] hydrogenases by density functional theory.
abstract: The inactive forms, unready (Ni-A, Ni-SU) and ready (Ni-B), of NiFe hydrogenases are modeled by examining the possibility of hydroxo, oxo, hydroperoxo, peroxo, and sulfenate groups in active-site models and comparing predicted IR frequencies and g tensors with those of the enzyme. The best models for Ni-A and Ni-SU have hydroxo (mu-OH) bridges between Fe and Ni and a terminal sulfenate [Ni-S(=O)Cys] group, although a hydroperoxo model for Ni-A is also quite viable, whereas the best model for Ni-B has only a mu-OH bridge. In addition, a mechanism for the activation of unready hydrogenase is proposed on the basis of the relative stabilities of sulfenate models versus peroxide models.
authors: Instituto de Catalisis, Consejo Superior de Investigaciones Cientificas, c/ Marie Curie, 2 Campus Cantoblanco, 28049 Madrid, Spain.
authors: Alejandro
authors: A
authors: Pardo
authors: Antonio L
authors: AL
authors: De Lacey
authors: Víctor M
authors: VM
authors: Fernández
authors: Yubo
authors: Y
authors: Fan
authors: Michael B
authors: MB
authors: Hall
mesh_terms: D001665:Binding Sites; D004789:Enzyme Activation; D006864:Hydrogenase / Q000737:chemistry*; D008958:Models, Molecular; D013057:Spectrum Analysis
chemical_list: C043296:nickel-iron hydrogenase; D006864:Hydrogenase