Sequence alignment of NDPKs whose structure has been solved.

<p>Sequence alignment was performed using ClustalW and mapped onto the secondary structure elements of <i>Mt</i>-NDPK, which derived from the crystal structure (PDB id 1k44) <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0057867#pone.0057867-Chen1" target="_blank">[13]</a>, by ESPript (<a href="http://espript.ibcp.fr/ESPript/ESPript/" target="_blank">http://espript.ibcp.fr/ESPript/ESPript/</a>). The Kpn loop was named after the killer of prune (Kpn) mutation of Drosophila. Among the fully conserved residues indicated on red background, the activesite residues are denoted with a blue star. Triangles indicate Arg80 and Asp93 which form the salt bridge discussed in this paper. The quaternary structure and the pdb code are indicated at the end of the sequences. The enzymes of the first group from <i>M. tuberculosis</i> to <i>B. halodenitrificans</i> are hexameric, while the second tetrameric or dimeric (<i>H. sp</i>. 593).