Ffp1, an ancestral Porphyromonas spp. fimbrillin
BackgroundLittle is known about fimbriae in the Porphyromonas genus. Besides fim and mfa, a third Porphyromonas gingivalis adhesin called Ffp1 has been described, and seems to be capital for outer membrane vesicle (OMV) production. ObjectiveWe aimed to investigate the distribution and diversity of type V fibrillin, particularly Ffp1, in the Porphyromonas genus. MethodsA bioinformatic phylogenomic analysis was conducted using all accessible Porphyromonas genomes in order to generate a domain search for fimbriae, using HMM profiles. ResultsFfp1 was found as the sole fimbrillin in all the analyzed genomes. After manual biocuration and 3D modeling, this protein was determined to be a type V fimbrillin, with a closer structural resemblance to a Bacteroides ovatus fimbrillin than to FimA or Mfa1 from P. gingivalis. ConclusionIt appears that Ffp1 represents ancestral fimbriae present in all Porphyromonas species. Additional investigations are necessary to elucidate the biogenesis of Ffp1 fimbriae and his potential role in OMV production and niche adaptation.