1. Center for Systems Biology, Massachusetts General Hospital, Boston, Massachusetts 02114, United States
2. Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02114, United States
3. Department of Chemistry, Kennedy College of Sciences, University of Massachusetts Lowell, Lowell, Massachusetts 01854, United States
4. Department of Chemistry, Soongsil University, Seoul 06978, South Korea
5. Department of Neurosurgery, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02114, United States
6. Department of Systems Biology, Harvard Medical School, Boston, Massachusetts 02115, United States