1. Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, CA 94720, USA.
2. Department of Plant and Microbial Biology, University of California at Berkeley, Berkeley, CA 94720, USA.
3. Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Xiqi Dao 32, Tianjin Airport Economic Area, Tianjin 300308, China.
4. Department of Chemistry, University of California at Berkeley, Berkeley, CA 94720, USA.
5. Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.