Fig. 3.

NMR titrations of mStau2 dsRBD1 and dsRBD2 with SRS2 + 5 RNA. a, c Overlay of ¹H,¹⁵N-HSQC spectra of dsRBD1 (a) or dsRBD2 (c) in absence and presence of SRS2 + 5 RNA. Resonance shifts and line broadening of several signals are observed for both domains. Note, that there are two sets of signals observed for dsRBD1, where only one set is affected by RNA binding. The second set of signals may reflect the presence of an alternate conformation of a region of dsRBD1. b, d Comparison of 1D imino NMR spectra of SRS2 + 5 RNA at different stoichiometric ratios with dsRBD1 (b) or dsRBD2 (d). Strong line broadening of imino signals is observed in presence of dsRBD2 but not dsRBD1, pointing at reduced RNA binding affinity for dsRBD1