FIG. 2.

Alignment of the ISXax1 DDE motif and the corresponding consensus sequence of the IS256 family (IS Finder database [http://www-is.biotoul.fr/is.html]). Highly conserved amino acids are shown in bold letters. For the IS256 family, uppercase letters indicate conservation within the family and lowercase letters indicate predominant amino acids. The numbers of amino acids between the motif regions are shown in parentheses. The N2, N3, and C1 domains containing the conserved DDE amino acids are also shown (19). The spacing between the three amino acids forming the DDE catalytic triad is variable depending upon IS256 family members (19).