1. Department of ChemistryUniversity of Science and Technology of China Hefei 230026 P. R. China
2. School of Food and Biological EngineeringKey Laboratory of Metabolism and Regulation for, Major Diseases of Anhui Higher Education InstitutesHefei University of Technology Hefei Anhui 230009 P. R. China
3. National Protein Science Technology CenterTsinghua University Beijing 100084 P. R. China
4. Institute of Intelligent MachinesChinese Academy of Sciences Hefei Anhui 230031 P. R. China