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J Biol Chem. 2011 Dec 23;286(51):44254-65. doi: 10.1074/jbc.M111.297242. Epub 2011 Oct 24.

Ultrahigh resolution and full-length pilin structures with insights for filament assembly, pathogenic functions, and vaccine potential.

Author information

1
Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.

Abstract

Pilin proteins assemble into Type IV pili (T4P), surface-displayed bacterial filaments with virulence functions including motility, attachment, transformation, immune escape, and colony formation. However, challenges in crystallizing full-length fiber-forming and membrane protein pilins leave unanswered questions regarding pilin structures, assembly, functions, and vaccine potential. Here we report pilin structures of full-length DnFimA from the sheep pathogen Dichelobacter nodosus and FtPilE from the human pathogen Francisella tularensis at 2.3 and 1 Å resolution, respectively. The DnFimA structure reveals an extended kinked N-terminal α-helix, an unusual centrally located disulfide, conserved subdomains, and assembled epitopes informing serogroup vaccines. An interaction between the conserved Glu-5 carboxyl oxygen and the N-terminal amine of an adjacent subunit in the crystallographic dimer is consistent with the hypothesis of a salt bridge between these groups driving T4P assembly. The FtPilE structure identifies an authentic Type IV pilin and provides a framework for understanding the role of T4P in F. tularensis virulence. Combined results define a unified pilin architecture, specialized subdomain roles in pilus assembly and function, and potential therapeutic targets.

PMID:
22027840
PMCID:
PMC3243539
DOI:
10.1074/jbc.M111.297242
[Indexed for MEDLINE]
Free PMC Article

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