1. Department of Molecular Biophysics and Biochemistry, Yale University, 266 Whitney Avenue, Post Office Box 208114, New Haven, CT 06520, USA.
2. Department of Molecular, Cellular and Developmental Biology, Yale University, 266 Whitney Avenue, Post Office Box 208114, New Haven, CT 06520, USA.
3. Department of Computer Science, Yale University, 266 Whitney Avenue, Post Office Box 208114, New Haven, CT 06520, USA.
4. Banting and Best Department of Medical Research, Department of Molecular and Medical Research, University of Toronto, Toronto, M5G 1L6, Ontario, Canada.