1. Department of Macromolecular Structures, Centro Nacional de Biotecnología (CNB-CSIC), Madrid, Spain.
2. Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada.
3. Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada.
4. Escuela Politécnica Superior, Universidad Autónoma de Madrid, Madrid, Spain.