Colonization factor antigen IV 203 CS5 fimbrial subunit FMS5_ECOLX PCF8775 CS5 pilin Major subunit of fimbriae. Fimbriae (also called pili), are polar filaments radiating from the surface of the bacterium to a length of 0.5-1.5 micrometers and numbering 100-300 per cell. They enable bacteria to colonize the epithelium of specific host organs. MKKNLLITSVLAMATVSGSVLAAVTNGQLTFNWQGVVPSAPVTQSSWAFVNGLDIPFTPGTEQLNITLDSNKDITARSVKPYDFFIVPVSGNVTPGAPVTRDTSANINSVNAFLSSVPVSNGFVGNKQLTLSTAVEAAKGEVAITLNGQALKVGSASPTVVTVASNKKESHISIDMNAKAAAADVAEGAAINFVAPVTFAVDI