1. 1Structural Genomics Consortium, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, U.S.A.
2. 2Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, U.S.A.
3. 3UNC Lineberger Comprehensive Cancer Center, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, U.S.A.