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Structural insights into microneme protein assembly reveal a new mode of EGF domain recognition
Author(s) -
Sawmynaden Kovilen,
Saouros Savvas,
Friedrich Nikolas,
Marchant Jan,
Simpson Peter,
Bleijlevens Boris,
Blackman Michael J,
SoldatiFavre Dominique,
Matthews Stephen
Publication year - 2008
Publication title -
embo reports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.584
H-Index - 184
eISSN - 1469-3178
pISSN - 1469-221X
DOI - 10.1038/embor.2008.179
Subject(s) - microneme , biology , toxoplasma gondii , microbiology and biotechnology , intracellular parasite , obligate , apicomplexa , intracellular , receptor , plasmodium falciparum , genetics , antibody , immunology , malaria , ecology
The obligate intracellular parasite Toxoplasma gondii , a member of the phylum Apicomplexa that includes Plasmodium spp., is one of the most widespread parasites and the causative agent of toxoplasmosis. Adhesive complexes composed of microneme proteins (MICs) are secreted onto the parasite surface from intracellular stores and fulfil crucial roles in host‐cell recognition, attachment and penetration. Here, we report the high‐resolution solution structure of a complex between two crucial MICs, TgMIC6 and TgMIC1. Furthermore, we identify two analogous interaction sites within separate epidermal growth factor‐like (EGF) domains of TgMIC6—EGF2 and EGF3—and confirm that both interactions are functional for the recognition of host cell receptor in the parasite, using immunofluorescence and invasion assays. The nature of this new mode of recognition of the EGF domain and its abundance in apicomplexan surface proteins suggest a more generalized means of constructing functional assemblies by using EGF domains with highly specific receptor‐binding properties.