1. Department of Structural Biology, Weizmann Institute of Science, Rehovot 76100, Israel
2. Department of Physics and Complex Systems, Weizmann Institute of Science, Rehovot 76100, Israel
3. Department of Chemical Research Support, Weizmann Institute of Science, Rehovot 76100, Israel
4. Max Planck Weizmann Center for Integrative Archaeology and Anthropology, Max Planck Institute for Evolutionary Anthropology, D-04103 Leipzig, Germany