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Publication Abstract from PubMed

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 A resolution, respectively. The DnFimA structure reveals an extended kinked N-terminal alpha-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.

Ultrahigh Resolution and Full-length Pilin Structures with Insights for Filament Assembly, Pathogenic Functions, and Vaccine Potential.,Hartung S, Arvai AS, Wood T, Kolappan S, Shin DS, Craig L, Tainer JA J Biol Chem. 2011 Dec 23;286(51):44254-65. Epub 2011 Oct 24. PMID:22027840^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.