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Helicolysins Emerge as a New Family of Metzincin Metallopeptidases in Host-pathogen Interactions

Arturo Rodríguez-Banqueri1, Theodoros Goulas2, Marina Girbal-González3

  • 1Proteolysis Laboratory, Department of Structural Biology, Molecular Biology Institute of Barcelona (CSIC), Barcelona Science Park, c/Baldiri Reixac, 15-21, 08028 Barcelona, Catalonia, Spain.

Journal of Molecular Biology
|July 29, 2026
PubMed

Insights

The study characterizes Helicobacter pylori HomA, revealing its role in bacterial adhesion and immune response modulation. HomA and related proteins, termed helicolysins, represent a new metallopeptidase subfamily involved in host-pathogen interactions.

Area of Science:

  • Microbiology
  • Structural Biology
  • Immunology

Background:

  • The Helicobacter pylori Hom family of outer-membrane proteins (OMPs) is linked to bacterial virulence.
  • Understanding HomA's structure and function is crucial for elucidating H. pylori pathogenesis.

Purpose of the Study:

  • To structurally and functionally characterize HomA from H. pylori.
  • To investigate HomA's role in bacterial adhesion and host cell signaling.
  • To define a new subfamily of metallopeptidases.

Main Methods:

  • Comparative in vivo analyses of wild-type and homA deletion mutant strains.
  • Recombinant protein production and characterization of HomA ectodomain (ECDHomA).
  • Site-directed mutagenesis, structural analysis (X-ray crystallography), bioinformatics, and AI-based structure prediction.
  • Biochemical characterization of a Capnocytophaga canimorsus homologue (canilysin).

Main Results:

  • HomA is involved in focal adhesion kinase phosphorylation and bacterial adhesion to human cells.
  • ECDHomA exhibits dimerization, acid resistance, and immunomodulatory activity, inducing pro-inflammatory responses.
  • Structural analysis revealed a two-domain organization with a unique 'Thr-turn'.
  • HomA homologues (helicolysins) were identified across various bacteria, including canilysin from C. canimorsus, which possesses specific metallopeptidase activity.

Conclusions:

  • The Hom family and canilysin constitute a new metzincin subfamily, helicolysins, characterized by a conserved Thr-turn and accessory N-terminal domain.
  • Helicolysins are implicated in host-pathogen interactions, bacterial adhesion, and immune modulation.
  • This work provides insights into the structure, function, and evolutionary significance of this protein family.
Keywords:
Helicobacter pyloricell adhesiongastric cancerhost-pathogen interactionsimmunomodulation

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