Lassa EN structures, flexibility and metal ion binding.

Abstract

<p><b>A,</b> Cartoon representation of the Lassa X1 and X3 structures after superposition. The α-helical bundles of X1 and X3 are respectively coloured in light and dark blue. The catalytic loop is highlighted in green and the Mn²⁺ ions of X3 are yellow spheres. The α-helical bundle closes the active site by the indicated rotation (blue arrow). The Lassa X2 structure has the same conformation as X3 (see <a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1005636#ppat.1005636.s005" target="_blank">S5A and S5B Fig</a>). <b>B,</b> The same structure superposition as <b>A</b>, with the active site residues as sticks, the X3 Mn²⁺ metal ions as yellow spheres and the ion coordination indicated by dashed green lines. <b>C,</b> Comparison of the Lassa X1 structure (light blue) and the previously reported Lassa EN structure in complex with Mg²⁺ [<a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1005636#ppat.1005636.ref016" target="_blank">16</a>] (light pink, PDB: 4MIW). The Mg²⁺ ions are shown as cyan spheres. <b>D,</b> The same superposition as <b>C,</b> with the active site residues as sticks and the bridging water molecules as small red spheres. The ion coordination and hydrogen bond network is shown by green dashed lines.</p