|Family type peptidase||U69.001 - AIDA-I self-cleaving autotransporter protein (Escherichia coli) (Escherichia coli), MEROPS Accession MER0152704 (peptidase unit: 847-904)|
|Content of family||Family U69 contains self-processing peptidases.|
Identifier created: MEROPS 8.5 (24 August 2009)|
The adhesin AIDA-I is a plasmid-encoded protein from Escherichia coli which plays a role in infantile diarrhaea in pigs. AIDA-I is a monomeric autotransporter secreted by the type Va secretory pathway and the extracellular portion is autocatalytically released.
|Catalytic type||Peptidase of unknown catalytic type|
|Active site||Although the active site residues responsible for the autoprocessing have not been unequivocally identified, site-directed mutagenesis of Asp878 or Glu897 prevented cleavage (Charbonneau et al., 2009).|
|Activities and specificities||Self-processing occurs at the Ser846Ala bond.|
|Molecular structure||AIDA-I is synthesized as a preproprotein with an N-terminal signal peptide promoting secretion into the periplasm. A C-terminal membrane-embedded domain, known as the AIDA-I translocator, permits secretion of part of the protein across the outer membrane. The extracellular domain, which is the adhesin, then releases itself, but remains associated with the translocator domain. The region of the protein responsible for cleavage lies between Ala667 and Thr953 (Charbonneau et al., 2009).|