 | Acta Crystallographica Section D Acta Crystallographica Section D BIOLOGICAL CRYSTALLOGRAPHY |
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![[Figure 5]](vr5062fig5mag.jpg)
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Figure 5
Structure of the putative active site. (a) Structural comparison of Tt-dNTPase (subunit) with the PDE4–AMP complex (PDB code 1ptw ) and the SpoT–ppGp complex (PDB code 1vj7 ). Structurally similar elements are displayed as thick red ribbons. The four conserved residues and ligand molecules (AMP and ppGp) are shown as stick representations in yellow and pink, respectively. Zn2+ or Mn2+ ions (green) and Mg2+ ions (grey) are shown as transparent spheres. (b) The putative active site of Tt-dNTPase. The difference Fourier map (2Fo − Fc map, σ = 1.0) is superimposed on the model drawn in stereo. (c) The model of the substrate (dATP) bound structure of the active site with Mg2+. The figure is drawn in stereo. The putative key residues are represented as sticks. The catalytic residues that are highly conserved among HD-superfamily proteins are coloured yellow. The residues highly conserved among Tt-dNTPase/Ec-dGTPase homologues that were predicted to be a ligand-binding site by computational search are coloured blue. The residues highly conserved among Tt-dNTPase/Ec-dGTPase homologues that are located near to the ribose moiety of dATP are coloured grey. The disordered region of the α3-α4 loop is represented as a dashed line. |
![[Figure 5]](vr5062fig5.jpg)
| BIOLOGICAL CRYSTALLOGRAPHY |
ISSN: 1399-0047
