Fig. 3.

ERK2 phosphorylation induces global conformational exchange in the kinase core. (A) Assigned methyls in 0P-ERK2 are shown as spheres, with k_ex values indicated by the color scale for individual fits of methyls that have R_ex > 4 s⁻¹. The asterisks and double asterisks indicate methyls having errors in k_ex > 50% and k_ex > 100%, respectively, with the latter methyls shown as black spheres. Methyls with no observable dynamics (R_ex ≈ 0 s⁻¹) are shown as white spheres. Thr183 and Tyr185 are shown as black sticks. (B) Residues in 2P-ERK2 with observable dynamics each fitted individually, colored as in A. (C) In 2P-ERK2, 19 methyls could be fit globally to a single rate constant (k_ex = 300 ± 10 s⁻¹) and population (p_A/p_B = 80/20 ± 0.6%), demonstrating global domain motion for residues throughout the kinase core. Residues in the MAP kinase insert subdomain could not be fit by a global process.