1. Laboratory for Molecular Infection Medicine Sweden, Department of Molecular Biology, Umeå Centre for Microbial Research, Umeå University, Umeå, Sweden.
2. Department of Crystallography and Structural Biology, Instituto de Química-Física “Rocasolano,” CSIC, Madrid, Spain.
3. Centro de Biología Molecular “Severo Ochoa,” Universidad Autónoma de Madrid–Consejo Superior de Investigaciones Científicas, Madrid, Spain.