1. Instituto de Parasitología y Biomedicina “López-Neyra”, Consejo Superior de Investigaciones Científicas; Granada Spain
2. York Structural Biology Laboratory, Department of Chemistry; University of York; York YO10 5DD UK
3. The Oxford Protein Production Facility, Research Complex at Harwell, Rutherford Appleton Laboratory; R92 Harwell Didcot Oxfordshire OX11 0FA UK