NMR supplement Hendrickson, W-A& Wuthrich, K Macromolecular 16. Leahy, D.J., Aukhil, I.& Erickson, H.P. 2.0 Cell 84 A K.D. thanks the Wellcome Trust and The queens 2D0i9 Riddiough. G. Nature Struct. Biol 18. sakaning. AK Kean. cel l8r.597-605i(eRw& by the Wellcome Trust. The authors acknowledge