Figure 5.

¹⁵N-HSQC NMR spectra of the α:ɛ:θ complex and PCS induced by Dy³⁺, Er³⁺ or Tb³⁺ ions. Resonance assignments are indicated for the cross-peaks observed in the absence of lanthanide ions. Arrows identify PCS induced by paramagnetic lanthanide ions bound to the active site of ɛ. (A) ¹⁵N-Alanine labeled ɛ in complex with α and θ. The spectra in the absence of lanthanide ion (black), with Er³⁺ (blue) and with Dy³⁺ (brown) are superimposed. (B) ¹⁵N-Threonine labeled ɛ in complex with α and θ. The spectra in the absence of lanthanide ion (black), with Er³⁺ (blue) and with Tb³⁺ (red) are superimposed.