1. Agilent Laboratories, Agilent Technologies, Santa Clara, California 95051,
United States
2. Department
of Chemistry, University of Wisconsin−Madison, Madison, Wisconsin
53706, United States
3. Genome
Center of Wisconsin, University of Wisconsin−Madison, Madison, Wisconsin
53706, United States
4. Department
of Biomolecular Chemistry, University of Wisconsin−Madison, Madison, Wisconsin
53706, United States