1. State Key Laboratory of Microbial Resources, Institute of Microbiology Chinese Academy of Sciences No. 1 Beichen West Road, Chaoyang DistrictBeijing 100101China
2. National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics Chinese Academy of Sciences Beijing 100101China
3. University of Chinese Academy of Sciences Beijing 100049China
4. Department of Microbiology Ohio State University Columbus OH 43210USA