1. Department of Chemistry, Box
H, Brown University, Providence, Rhode
Island 02912-9108, United States
2. Key Laboratory of Combinatorial
Biosynthesis and Drug Discovery (Wuhan University), Ministry of Education, and Wuhan University School of Pharmaceutical
Sciences, Wuhan 430071, P. R. China
3. Key Laboratory of Microbial Metabolism and School of Life Sciences & Biotechnology, Shanghai Jiaotong University, Shanghai 200030, P. R. China