Structure and function of repetitive sequence elements associated with a highly polymorphic domain of the Neisseria meningitidis PilQ protein

摘要: Summary Secretins are a large family of proteins associated with membrane translocation macromolecular complexes, and subset this family, termed PilQ proteins, is required for type IV pilus biogenesis. We analysed the status expression in Neisseria meningitidis (Mc) found that π mutants were non-piliated deficient pilusassociated phenotypes. Sequence analysis 58 portion pilQ ORF serogroup B Mc strain 44/76 showed presence seven copies repetitive sequence element, contrast to situation N. gonorrhoeae (Gc) strains, which carry either two or three repeat. The derived amino acid consensus nucleotide repeat was an octapeptide PAKQQAAA, designated as small basic (SBR). This gene segment studied more detail collection 52 strains diverse origin by screening variability size PCR-generated DNA fragments spanning SBRs. These harbour from four element. No association between number serogroup, geographic multilocus genotype evident. polymorphic elements unprecedented within secretin family. To address potential function containing domain, constructed so express chimeric molecules SBR repeats increased domain replaced toto corresponding region Pseudomonas aeruginosa (Pa) protein. Although expressing SBRs identical parent phenotypes, equivalent Pa had eightfold reduction level. findings suggest influences quantitatively but not qualitatively.