PROSITE documentation PDOC00886Fimbrial biogenesis outer membrane usher protein signature
In Gram-negative bacteria the biogenesis of fimbriae (or pili) requires a two-component assembly and transport system which is composed of a periplasmic chaperone (see <PDOC00552>) and an outer membrane protein which has been termed a molecular 'usher' [1,2,3]. The protein is rather large (from 86 to 100 Kd) and seems to be mainly composed of membrane-spanning β-sheets, a structure reminiscent of porins. Known members of this family are listed below:
- Escherichia coli papC for P pili.
- Escherichia coli afaC for AFA-III adhesin.
- Escherichia coli aggC for AAF/I fimbriae.
- Escherichia coli cssD for CS6 antigen.
- Escherichia coli faeD for K88 pili.
- Escherichia coli fanD for K99 pili.
- Escherichia coli fasD for 987P fimbria.
- Escherichia coli fimD for type 1 fimbriae.
- Escherichia coli focD for F1C fimbriae.
- Escherichia coli htrE for a yet unknown pilin.
- Escherichia coli CS3-2 for CS3 pili.
- Bordetella pertussis fhaA (or fimC) for filamentous hemagglutinin and fimbria.
- Haemophilus influenzae hifC for type b pili.
- Klebsiella pneumoniae mrkC for type 3 pili.
- Proteus mirabilis pmfC for PMF fimbriae.
- Salmonella enteritidis sefC for sef14 fimbriae.
- Salmonella typhimurium lpfC for long polar fimbriae.
- Yersinia enterocolitica myfC for myf fimbriae.
- Yersinia pestis caf1A for F1 capsule antigen.
- Escherichia coli hypothetical protein ybgQ.
- Escherichia coli hypothetical protein ycbS.
- Escherichia coli hypothetical protein yehB.
- Escherichia coli hypothetical protein yfcU.
- Escherichia coli hypothetical protein yhcD.
- Escherichia coli hypothetical protein yqiG.
- Escherichia coli hypothetical protein yraJ.
The degree of sequence similarity of these proteins is not very high. However they share a number of characteristics. One them is the presence of two pairs of cysteines, the first one is located in the N-terminal part and the second at the C-terminal extremity. They are probably involved in disulfide bonds. The best conserved region is located in the central part of these proteins and can be used as a signature pattern.
Expert(s) to contact by email: Last update:November 1997 / Text revised.
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| 1 | Authors | Jacob-Dubuisson F. Striker R. Hultgren S.J. |
| Source | J. Biol. Chem. 269:12447-12455(1994). |
| 2 | Authors | Schifferli D.M. Alrutz M.A. |
| Title | Permissive linker insertion sites in the outer membrane protein of 987P fimbriae of Escherichia coli. | |
| Source | J. Bacteriol. 176:1099-1110(1994). | |
| PubMed ID | 7906265 |
| 3 | Authors | van Rosmalen M. Saier M.H. Jr. |
| Source | Res. Microbiol. 144:507-527(1993). |
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