(A) The genetic organisation of gtxA, gtxC and their flanking genes in G. anatis 12656-12. Arrows indicate ORF. A predicted transcriptional terminator is indicated downstream of gtxC. (B) Organisation of GtxA. K indicates conserved lysine residues (Lys1484 and Lys1607). The glycine aspartate-rich region (position 1640–1830) is marked. (C) Alignment of the 15 repeats in the N-terminal domain of GtxA, the alignment was generated with Radar . Numbers to the left indicate amino acid position in GtxA. Positions where the amino acid are identical (black) or similar (grey) in more than 50% of the repeats are marked.