1. State Key Laboratory of Magnetic Resonance and Atomic Molecular Physics; Wuhan Center for Magnetic Resonance, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences; Wuhan 430071 China
2. Department of Chemistry, College of Science; Huazhong Agricultural University; Wuhan 430070 China
3. Department of Chemistry and Biochemistry, and the Northeast Structural Genomics Consortium; Miami University; Oxford Ohio 45056