1. Department of Biochemistry and Biophysics, Arrhenius Laboratories for Natural Sciences, Stockholm University 10691 Stockholm Sweden
2. Unité de Biochimie Physiologique, Université Catholique de Louvain, Croix du Sud, 2–20 B‐1348 Louvain‐la‐Neuve Belgium
3. Center of Excellence in Structural Biology, Department of Biochemistry, Cellular and Molecular Biology, University of Tennessee at Knoxville Knoxville Tennessee 37916 USA