Figure 3.

¹⁵N-HSQC NMR spectra of ɛ in complex with θ. The cross-peaks are assigned with the residue numbers. (A) ¹⁵N-Ala labeled ɛ in complex with unlabeled θ. The circle identifies a set of unassigned peaks indicative of sample heterogeneity. They were not observed for the α:ɛ:θcomplex (Figure 5A, spectral region not shown). (B) ¹⁵N-Thr labeled ɛ in complex with unlabeled θ. The asterisks label peaks which were not observed in the spectra of ɛ186 or the α:ɛ:θ complex, indicating sample heterogeneity.