Characterizing the interaction between F12-ATP and GST-HEPN.

<p>A. Overlay of ¹⁵N,¹H-HSQC NMR spectra of 200 μM ¹⁵N-HEPN alone (<i>red</i>) and following the addition of GTP (50 μM GTP in <i>green</i> and 100 μM in <i>blue</i>). Residues that showed chemical shift perturbations in the presence of GTP were identified from the assigned HEPN spectrum and labeled. B. Residues involved in GTP-binding are mapped onto the HEPN crystal structure (PDB: 3O10) and labeled in <i>blue</i>. Malonate ions present in the crystal structure are presented in stick representation, with their oxygen atoms labeled in <i>red</i>. C. Overlay of ¹⁵N,¹H-HSQC NMR spectra of 110 μM ¹⁵N-HEPN alone (<i>red</i>) and following the addition of F12-ATP (55 μM in <i>green</i> and 110 μM in <i>blue</i>). D. Residues involved in F12-ATP-binding are mapped onto the HEPN crystal structure. Residues involved in both F12-ATP and GTP-binding are labeled in <i>blue</i> and additional residues that shifted during the F12-ATP titration are labeled in <i>red</i>.