1. a State Key Laboratory for Structural Chemistry of Unstable and Stable Species , Centre for Molecular Science , Institute of Chemistry , Chinese Academy of Sciences , Beijing 100080, P.R. China
2. c Department of Molecular Biomimetics , Uppsala University , S-75236 Uppsala, Sweden
3. b Department of Biophysics , School of Basic Medical Sciences , Peking University , Beijing 100083, P.R. China
4. d Department of Biochemistry , Centre for Chemistry and Chemical Engineering , Lund University , P.O. Box 124, S-22100 Lund, Sweden