1. Department of ChemistryUniversity of California Riverside CA 92521 USA
2. Department of Molecular and Medical PharmacologyUniversity of California Los Angeles CA 90095 USA
3. Key Laboratory of Molecular BiophysicsInstitute of BiophysicsSchool of SciencesHebei University of Technology Tianjin 300401 China
4. Institute for Systems Biology Seattle WA 98109 USA