Background: SAAT

AIDA-I belongs to a family of autotransporters that have a specific imperfectly repeated sequence of 19 amino acids in their N terminus. The consensus of these repeats is:

-GG-A--T-(I/L/V)N-GG-(Q/L)-(V/I/L)-

This motif is very characteristic. Morevover, members of this family all mediate bacterial auto-aggregation. It is therefore thought that they are able of self-recognition. The family comprises 3 E. coli proteins: Ag43, TibA and AIDA-I.