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Host cell invasion by apicomplexan parasites: insights from the co-structure of AMA1 with a RON2 peptide

Michelle L Tonkin1, Magali Roques, Mauld H Lamarque

  • 1Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia V8W 3P6, Canada.

Science (New York, N.Y.)
|July 23, 2011
PubMed

Insights

The structure of Toxoplasma gondii apical membrane antigen 1 (TgAMA1) complexed with a rhoptry neck protein 2 (RON2) peptide was determined. This reveals a stepwise assembly mechanism for the moving junction complex essential for parasite invasion.

Area of Science:

  • Parasitology
  • Structural Biology
  • Molecular Mechanisms of Host-Pathogen Interaction

Background:

  • Apicomplexan parasites, including *Toxoplasma gondii* and *Plasmodium* species, employ a moving junction (MJ) complex for host cell invasion.
  • The MJ complex facilitates invasion through interactions between parasite proteins, such as apical membrane antigen 1 (AMA1), and host cell components via rhoptry neck proteins (RONs).

Purpose of the Study:

  • To elucidate the structural basis of the moving junction complex formation.
  • To understand the molecular interactions between *Toxoplasma gondii* AMA1 and RON2 peptide.
  • To provide insights into apicomplexan host cell invasion mechanisms.

Main Methods:

  • X-ray crystallography was used to determine the structure of the TgAMA1-RON2 peptide complex.
  • High-resolution structural analysis at 1.95 angstroms.

Main Results:

  • The study determined the 1.95 angstrom resolution structure of the TgAMA1-RON2 peptide complex.
  • A stepwise assembly mechanism was revealed, characterized by an extensive buried surface area.
  • This extensive interaction confers mechanical stability to the MJ complex during invasion.

Conclusions:

  • The determined structure provides critical insights into the molecular mechanisms of apicomplexan parasite invasion.
  • The findings offer a structural foundation for the rational design of novel therapeutics targeting these pathogens.
  • Understanding the TgAMA1-RON2 interaction is key to developing strategies against global apicomplexan diseases.

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