Mononuclear iron hydrogenase

The active site of the mononuclear Fe-hydrogenase (Hmd) is a unique non-heme Fe enzyme involved in the catalytic activation of molecular H-2. Apart from the nitrile hydratases and the peptidyl deformylases it is the only non-heme enzyme that has a redox inactive Fe in its active site. Naturally it has caught the attention of biochemists, bio-physicists, synthetic inorganic chemists and computational chemists alike since its isolation in the early 1990s. Our renewed interest in alternative energy has fuelled research in understanding this simplest, in terms of active site organization, of the known hydrogenases over the last two decades. A significant amount of synthetic work has led to very successful small molecule structural mimics of the active site. In-depth computational studies have led to a few mechanistic proposals for the heterolytic H-2 cleavage reaction catalysed by this enzyme. There have been some recent developments in understanding its geometric and electronic structure and its contribution to its reactivity. This review provides and up-to-date overview of the research in this area. (C) 2012 Elsevier B.V. All rights reserved.