AvrRpm1 exhibits structural homology to the catalytic domain of Poly-ADP-ribosyl polymerase (PARP).

<p>(<b>A</b>) Sequence alignment of DT family ADP-ribosylating proteins <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0042633#pone.0042633-Yates1" target="_blank">[35]</a> and the four AvrRpm1 family proteins illustrating key regions of conservation. Secondary structure for each region is shown above. Highly conserved residues are highlighted in blue. Red carets denote the catalytic triad of PARP. (<b>B</b>) Homology model of the AvrRpm1 reference allele (copper) from <i>P. syringae</i> pv. <i>maculicola</i> M6 (<i>Psm</i> M6) with the catalytic domain of Poly-ADP-ribosyl polymerase 1 (PARP-1; PDB ID: 3GJW) (silver). The side chains for residues highlighted in (<b>A</b>) are denoted by dark blue (AvrRpm1) and light blue (PARP-1). Residues in the catalytic triad are labeled according to AvrRpm1. “N” and “C” represent the amino- and carboxy-terminus of the protein respectively. Independent homology models for the remaining three AvrRpm1 family members from (<b>B</b>) <i>P. syringae</i> pvs. <i>syringae</i> B728a (<i>Psy</i> B728a), (<b>C</b>), <i>pisi</i> race 6 (<i>Ppi</i> race 6) (<b>D</b>), and <i>phaseolicola</i> 2708 (<i>Psp</i> 2708).