The non-catalytic domain of PDIR contains a conserved positively charged surface.

<p>(A) Mapping of sequence conservation on the surface of the human PDIR domain; invariant residues are colored green. (B) Surface charge; the positively charged (blue) surface coincides with the conserved region. Negative charge is in red. (C) The conserved lysine and arginine residues are located on helices α1 and α3. The domain orientation in panels (B) and (C) is identical to that in the left view of the panel (A).</p

Crystal contacts identify a putative binding surface for hydrophobic polypeptides.

<p>(A) The Leu143 and Trp144 from the C-terminal tail of the crystallized fragment bind to a pocket in an adjacent PDIR molecule. (B) The base of the pocket is lined with hydrophobic residues, while Glu31 and Arg46 make hydrogen bonds with backbone amide and carbonyl groups.</p

¹H,¹⁵N-correlation HSQC spectra of GtgE.

<p>(A) GtgE(17–214), dispersion of peaks is characteristic of a well-folded protein. (B) Superposition of HSQC spectra of GtgE(17–214) (red) and GtgE(79–214) (cyan).</p

Statistics of data collection and refinement.

<p>Statistics of data collection and refinement.</p

Effects of MgCl₂ and EDTA on the interaction between F12-ATP and GST-HEPN.

<p>A. F12-ATP vs. GST-HEPN FP titration was carried out in the presence of 1 mM MgCl₂ and increasing concentrations of EDTA. B. F12-ATP vs. GST-HEPN FP titration with increasing concentrations of EDTA alone. C. EDTA-interacting residues are labeled in <i>blue</i> on the HEPN crystal structure. D. G-tetra-P-binding residues are mapped onto HEPN. G-tetra-P-binding residues that are also involved in GTP-binding are labeled in <i>blue</i> and additional residues only involved in G-tetra-P-binding are labeled in <i>red</i>.</p

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>.</p