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P-pilus
P fimbriae (also known as pyelonephritis-associated pili) or P pili or Pap are chaperon-usher type (specifically of the π family) fimbrial appendages found on the surface of many '' Escherichia coli'' bacteria. The P fimbriae is considered to be one of the most important virulence factor in uropathogenic ''E. coli'' and plays an important role in upper urinary tract infections. P fimbriae mediate adherence to host cells, a key event in the pathogenesis of urinary tract infections. Structure and expression P fimbriae are large, linear structures projecting from the surface of the bacterial cell. With lengths of 1-2um, the pili can be larger than the diameter of the bacteria itself. The main body of the fimbriae is composed of approx. 1000 copies of the major fimbrial subunit protein PapA, forming a helical rod. The short fimbrial tip is made of the subunits PapK, PapE, PapF and the tip adhesin PapG, which mediates the binding. The fimbriae is assembled by a chaperone-usher s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chaperone-Usher Fimbriae
Chaperone-usher fimbriae (CU) are linear, unbranching, Bacterial outer membrane, outer-membrane Pilus, pili secreted by gram-negative bacteria through the chaperone-usher system rather than through type IV secretion or extracellular nucleation systems. These fimbria (bacteriology), fimbriae are built up out of modular pilus subunits, which are transported into the periplasm in a Sec pathway, Sec dependent manner. Chaperone-usher secreted fimbriae are important pathogenicity factors facilitating host colonisation (biology), colonisation, localisation and biofilm formation in clinically important species such as UPEC, uropathogenic ''Escherichia coli'' and ''Pseudomonas aeruginosa''. Structure Overall All chaperone/usher systems are found within Operon, gene clusters consisting of at least an Fimbrial usher protein, usher, a chaperone (protein), chaperone and one or more fimbriae subunits. Overall the system includes periplasmic chaperones, periplasmic and extracellular pilin, pilus ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
