1. Department of Chemistry, University of Connecticut, Storrs, CT 06269, USA
2. Department of Biology, New York University, New York, NY 10003, USA
3. Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531, Japan
4. Rudolf Virchow Center for Experimental Biomedicine, Institute for Structural Biology, University of Würzburg, 97080 Würzburg, Germany