1. Environmental Geochemistry Group, LGIT, UMR 5559, Université Joseph Fourier and CNRS, BP 53, 38041 Grenoble, France, Institut de Biologie Structurale—J.P. Ebel, UMR 5075, CNRS, F-38027 Grenoble, France, CEA, F-38054 Grenoble, France, UJF, F-38000 Grenoble, France, Institut Néel, CNRS, 38042 Grenoble Cedex 9, France, and Molecular and Cellular Biology, Belgian Center for Nuclear Energy, SCK•CEN, B-2400 Mol, Belgium