国家自然科学基金资助项目81274013;国家自然科学基金重点项目资助81130069;人事部留学人员择优资助项目2009-2012;国家“重大新药创制”科技重大专项资助项目2011ZX09307-002-01;This study was supported by the National Natural Science Foundation of China81274013;the National Natural Science Foundation in Key Projects81130069;The Personnel Department Students Studying Abroad Preferred-Aid Project2009-2011;China National Key High-Tech Innovation Project for the R&D of Novel Drugs2011ZX09307-002-01