1 Department of Medicinal Chemistry, Key Laboratory of Chemical Biology (MOE), School of Pharmacy, Shandong University, Jinan, Shandong 250012, China.
2 Department of Medicinal Chemistry, Key Laboratory of Chemical Biology (MOE), School of Pharmacy, Shandong University, Jinan, Shandong 250012, China; State Key Laboratory of Microbial Technology, Shandong University, Jinan, Shandong 250100, China. Electronic address: mli@sdu.edu.cn.