卫生部重大疾病专项基金2013ZX10003006-001-001;生物大分子国家重点实验室开放基金2013kf01;科技部重大仪器专项基金2011YQ03013404资助项目.This work was supported by grants from The Ministry of Health of The People's Republic of China2013ZX10003006-001-001;The National Laboratory of Biomacromolecules2013kf01;The Ministry of Science and Technology of People's Republic of China2011YQ03013404