1. State Key Laboratory of Bioorganic and Natural Products Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Rd., Shanghai 200032, China
2. Laboratory of Microbial Metabolism and School of Life Science & Biotechnology, Shanghai Jiaotong University, 1954 Huashan Rd., Shanghai 200030, China
3. Division of Pharmaceutical Sciences, School of Pharmacy, University of Wisconsin-Madison, 777 Highland Ave., Madison, Wisconsin 53705