1. Instituto de Biotecnología Universidad Nacional Autónoma de México Cuernavaca Mexico
2. Structural Biology Section, Research Technologies Branch National Institute of Allergy and Infectious Diseases, National Institutes of Health Bethesda Maryland USA
3. Vaccine Research Center, National Institute of Allergy and Infectious Diseases National Institutes of Health Bethesda Maryland USA
4. Shemyakin‐Ovchinnikov Institute of Bioorganic Chemistry Russian Academy of Sciences Moscow Russian Federation