The SAIL-SARS-CoV NP CTD sample contained 0.5 mM (10% D 2 O buffer) and 0.5 mM (100% D 2 O buffer) of the SAIL SARS-CoV NP CTD in NMR buffer [10 mM sodium phosphate pH 6.0, 50 mM NaCl, 1 mM EDTA, 1 mM 2,2-dimethyl-2-silapentane-5-sulfonate, 0.01% NaN 3 , 10% D 2 O, and Complete Mini protease inhibitor mix (Roche)].