1. Department of Biological Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
2. Department of Fine Chemistry, Seoul National University of Science and Technology, Seoul 139-743, Korea
3. Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, Michigan 48109, United States
4. Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, United States
5. Department of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48105, United States
6. Applied Physics Program, University of Michigan, Ann Arbor, Michigan 48105, United States