1. Beijing Institute of Technology
2. State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, Beijing
3. Department of Structural Biology, Stanford University, Stanford, California 94305, USA
4. Department of Electrical Engineering and Computer Sciences,University of California
5. Department of Structural Biology, Stanford University School of Medicine, Stanford, California, 94305, USA
6. Tsinghua University