NMR
Detailed NMR methods can be found in supplemental material. Briefly, triple-resonance and NOESY spectra were collected on 0.1-1 mM protein samples in PBS using either a 600 or 800 MHz Agilent DD2 console equipped with cryogenically cooled probe. Backbone and side-chain assignments and T1/T2 relaxation times for the oxidized samples were obtained using standard triple resonance techniques employing either the standard VARIAN Biopack or modified BEST-TROSY pulse sequences as described previously[22-25].