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Cryo-EM structure of the native assembled Mfa type V pilus from the periodontal pathogen Porphyromonas gingivalis

Satoshi Shibata1,2,3, Hideyuki Matsunami4, Kazuhisa Ouhara5

  • 1Molecular Cryo-Electron Microscopy Unit, Okinawa Institute of Science and Technology Graduate University, Okinawa, Japan. sshibata@tottori-u.ac.jp.

Communications Biology
|June 23, 2026
PubMed

Insights

The Mfa pilus structure from Porphyromonas gingivalis reveals protease-mediated assembly, crucial for periodontal disease. This finding offers new targets for antimicrobial drugs against P. gingivalis infections.

Area of Science:

  • Microbiology
  • Structural Biology
  • Biochemistry

Background:

  • Porphyromonas gingivalis causes periodontal disease.
  • Type V pili (Fim and Mfa) are key virulence factors.
  • Mfa pilus structure and assembly were previously unknown.

Purpose of the Study:

  • Determine the structure of the polymerized Mfa1 stalk pilin.
  • Elucidate the Mfa pilus assembly mechanism.
  • Identify potential antimicrobial drug targets.

Main Methods:

  • Cryo-electron microscopy (3.0 Å resolution).
  • Atomic model determination of polymerized Mfa1.
  • Analysis of the streptococcal-binding region.

Main Results:

  • Mfa1 pilins polymerize via protease-mediated strand exchange.
  • A Ca2+ ion is retained, modulating immune recognition.
  • The streptococcal-binding region's architecture was elucidated.
  • Protease-mediated strand exchange is confirmed as a universal Type V pilus assembly mechanism.

Conclusions:

  • The Mfa pilus structure provides insights into P. gingivalis pathogenicity.
  • The findings support protease-mediated strand exchange as a universal assembly mechanism for Type V pili.
  • The structure offers potential targets for novel antimicrobial therapies against periodontal and systemic diseases.

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