1. Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405, United States
2. Department of Structure of Macromolecules, Centro Nacional de Biotecnología (CNB-CSIC), Darwin 3, 28049 Madrid, Spain
3. Centro Nacional
de Microbiología/ISCIII, 28220 Majadahonda, Madrid, Spain
4. X-ray Science Division, Advanced Photon Source, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439, United States