Localization of PipX residues discussed in this work. Details of interactions between one PipX monomer and P_II

<p>(<b>A</b>) <b>or NtcA</b> (<b>B</b>) <b>are shown in the P_II-PipX (PDB file 2XG8) and NtcA-PipX complexes (PDB file 2XKO).</b> PipX structures are represented in blue ribbon while surface representation and pale colours are used for P_II (subunits in grey, yellow and pink) and NtcA (grey and cyan). In each case, the enlargement of PipX to the right shows relevant side chains of residues mutated to alanine (except Q34, mutated to glutamate). Mutated residues that increase, decrease or do not affect PipX toxicity are colored in red, green, and gold, respectively.