title: Recombinant Porphyromonas gingivalis FimA preproprotein expressed in Escherichia coli is lipidated and the mature or processed recombinant FimA protein forms a short filament in vitro.
abstract: The gram-negative anaerobic bacterium Porphyromonas gingivalis is an etiologically important pathogen for chronic periodontal diseases in adults. Our previous study suggested that the major structural components of both Fim and Mfa fimbriae in this organism are secreted through their lipidated precursors. In this study, we constructed Escherichia coli strains expressing various fimA genes with or without the 5'-terminal DNA region encoding the signal peptide, and we determined whether lipidation of recombinant FimA proteins occurred in E. coli. Lipidation occurred for a recombinant protein from the fimA gene with the 5'-terminal DNA region encoding the signal peptide but not for a recombinant protein from the fimA gene without the signal-peptide-encoding region, as revealed by [3H]palmitic acid labeling experiments. A TLR2-dependent signaling response was induced by the recombinant protein from the fimA gene with the signal-peptide-encoding region but not by a recombinant protein from the fimA gene with the signal-peptide-encoding region that had a base substitution causing an amino acid substitution (C19A). Electron microscopic analysis revealed that recombinant FimA (A-47 - W-383) protein was autopolymerized to form filamentous structures of about 80 nm in length in vitro. The results suggest that FimA protein, a major subunit of Fim fimbriae, is transported to the outer membrane by the lipoprotein sorting system, and a mature or processed FimA protein on the outer membrane is autopolymerized to form Fim fimbriae.
authors.affiliation: Department of Microbiology and Oral Infection, Nagasaki University Graduate School of Biomedical Sciences, 1-7-1 Sakamoto, Nagasaki 852-8588, Japan. m-shoji@nagasaki-u.ac.jp
authors.forename: Mikio
authors.initials: M
authors.lastname: Shoji
authors.forename: Atsutoshi
authors.initials: A
authors.lastname: Yoshimura
authors.forename: Hidenobu
authors.initials: H
authors.lastname: Yoshioka
authors.forename: Akemi
authors.initials: A
authors.lastname: Takade
authors.forename: Yasuko
authors.initials: Y
authors.lastname: Takuma
authors.forename: Hideharu
authors.initials: H
authors.lastname: Yukitake
authors.forename: Mariko
authors.initials: M
authors.lastname: Naito
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Hara
authors.forename: Shin-Ichi
authors.initials: S
authors.lastname: Yoshida
authors.forename: Koji
authors.initials: K
authors.lastname: Nakayama
mesh_terms: D000818:Animals; D016466:CHO Cells; D006224:Cricetinae; D003412:Cricetulus; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D036781:Fimbriae Proteins / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure; D010861:Fimbriae, Bacterial / Q000378:metabolism / Q000648:ultrastructure; D006801:Humans; D050356:Lipid Metabolism; D016966:Porphyromonas gingivalis / Q000235:genetics; D011498:Protein Precursors / Q000235:genetics / Q000378:metabolism*; D021382:Protein Sorting Signals; D011994:Recombinant Proteins / Q000378:metabolism / Q000648:ultrastructure; D051195:Toll-Like Receptor 2 / Q000378:metabolism
chemical_list: D011498:Protein Precursors; D021382:Protein Sorting Signals; D011994:Recombinant Proteins; C495342:TLR2 protein, human; D051195:Toll-Like Receptor 2; C063055:fimbrillin; D036781:Fimbriae Proteins