Figure 2 | Scientific Reports

Figure 2

From: The PHP domain of PolX from Staphylococcus aureus aids high fidelity DNA synthesis through the removal of misincorporated deoxyribo-, ribo- and oxidized nucleotides

Figure 2Figure 2

Sequence alignment of saPolX with ttPolX and homology model of saPolX. (A) The proteins encoded by genes SACOL1153 (saPolX) and TTHA1150 (ttPolX) from organisms S. aureus and T. thermophilus, respectively are aligned and compared. The residues in grey color represent the conserved 8-kDa domain, light blue color residues show fingers, green color shows palm, pink-colored residues show thumb and orange residues show PHP domain. The residues in three conserved HhH motifs are shown in dark blue color and underlined. The catalytic residues critical for DNA polymerase activity (including D193) of saPolX are highlighted by yellow boxes. The nine residues highlighted in green boxes indicate the residues, including H435 (underlined) that are critical for the exonuclease activity of ttPolX. (B) Homology model for saPolX. The homology model for saPolX was created using ttPolX binary structure as a template (PDB code: 3AU2) at the SWISS-MODEL server. The conserved 8-kDa, fingers, palm, thumb and PHP domains are displayed in grey, light blue, green, pink and orange color. The inset figure shows a close up of the PHP domain with the H435 displayed in stick representation and colored according to the atom. The H435 residue is known to be important for exonuclease activity and was selected for substitution with Ala (H435A) to prepare a mutant version that is incapable of exonuclease activity.

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