| Autotransporter beta-domain | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Structure of the translocator domain of a bacterial autotransporter.[1] | |||||||||
| Identifiers | |||||||||
| Symbol | Autotransporter | ||||||||
| Pfam | PF03797 | ||||||||
| InterPro | IPR005546 | ||||||||
| PROSITE | PDOC51208 | ||||||||
| SCOP | 1uyn | ||||||||
| TCDB | 1.B.12 | ||||||||
| OPM family | 28 | ||||||||
| OPM protein | 1uyo | ||||||||
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In molecular biology an autotransporter domain is a structural domain found in some outer membrane proteins.
Translocation of polypeptide chains through the outer membrane of Gram-negative bacteria is termed secretion. Secretion occurs via a number of different pathways in this type of bacterium. One of these pathways, known as the type V(a) secretion pathway is exemplified by the prototypical IgA1 Protease of Neisseria gonorrhoeae [2]. In fact the type V(a), or autotransporter secretion pathway, constitutes the largest number of secreted virulence factors of any one of the seven known types of secretion from Gram-negative bacteria.
The protein domain shown to be absolutely necessary to mediate secretion through the outer membrane is contained within the C-terminal portion of the translated protein itself, which undergoes post-translational modification prior to secretion of a passenger domain, hence proteins secreted in this way are called autotransporters. The C-terminal translocator domain corresponds to an outer membrane beta-barrel domain. The N-terminal passenger domain is translocated across the membrane, and may or may not be cleaved from, and may or may not remain associated with, the translocator domain[3]. In those proteins where the cleavage is auto-catalytic, the peptidase domains belong to MEROPS peptidase families S6 and S8. Passenger domains structurally characterised to date have been shown to be dominated by a protein fold known as a beta helix, the folding of which is thought to be intrinsically linked to its method of outer membrane translocation.