Following their transport across the OM, many passenger domains are released from the ОІ domain by a proteolytic cleavage. Passenger domains are highly divergent in sequence and mediate a wide range of virulence functions ( 9). They consist of two domains, an N-terminal extracellular domain (passenger domain) that often exceeds 100 kDa in length, and a C-terminal в€ј30-kDa ОІ barrel domain (ОІ domain) that anchors the protein in the outer membrane (OM) ( 4).

Our results strongly suggest that the conserved residues are required to position the О±-helical segment for the cleavage reaction and are not required to promote passenger domain secretion.ДЄutotransporters are a large superfamily of virulence factors produced by Gram-negative bacteria. Although the mutation of conserved residues that surround the cleavage site has been reported to impair both the translocation and cleavage of the passenger domain of a SPATE called Tsh, we show here that the mutation of the same residues in another SPATE (EspP) affects only passenger domain cleavage. Following its secretion, the passenger domain of the serine protease auto transporters of the E nterobacteriaceae (SPATEs) and the pertactin family of Bordetella pertussis autotransporters is released from the ОІ domain through an intrabarrel autoproteolytic cleavage of the О±-helical segment. Available evidence indicates that an О±-helical segment that spans the passenger domain-ОІ domain junction is embedded inside the ОІ domain at an early stage of assembly. The ОІ domain promotes the translocation of the passenger domain across the OM by an unknown mechanism.

Autotransporters are a superfamily of virulence factors produced by Gram-negative bacteria that are comprised of an N-terminal extracellular domain (passenger domain) and a C-terminal ОІ barrel domain (ОІ domain) that resides in the outer membrane (OM).

Tajima pulse break segments