[1] Univ Toronto, Banting & Best Dept Med Res, Toronto, ON M5G 1L6, Canada
[2] Univ Toronto, Dept Mol & Med Genet, Toronto, ON M5G 1L6, Canada
[3] Univ Toronto, Ctr Excellence, Prot Engn Network, Toronto, ON M5G 1L6, Canada
[4] Univ Toronto, Dept Biochem, Toronto, ON M5G 1L6, Canada
[5] Univ Toronto, Dept Chem, Toronto, ON M5G 1L6, Canada