Download MendeleyMicroneme protein 5 regulates the activity of toxoplasma subtilisin 1 by mimicking a subtilisin prodomain.
Saouros, S., Dou, Z., Henry, M., Marchant, J., Carruthers, V.B., Matthews, S.(2012) J Biol Chem 287: 36029-36040
- PubMed: 22896704
- DOI: https://doi.org/10.1074/jbc.M112.389825
- Primary Citation of Related Structures:
2LU2 - PubMed Abstract:
Toxoplasma gondii is the model parasite of the phylum Apicomplexa, which contains obligate intracellular parasites of medical and veterinary importance. Apicomplexans invade host cells by a multistep process involving the secretion of adhesive microneme protein (MIC) complexes. The subtilisin protease TgSUB1 trims several MICs on the parasite surface to activate gliding motility and host invasion. Although a previous study showed that expression of the secretory protein TgMIC5 suppresses TgSUB1 activity, the mechanism was unknown. Here, we solve the three-dimensional structure of TgMIC5 by nuclear magnetic resonance (NMR), revealing that it mimics a subtilisin prodomain including a flexible C-terminal peptide that may insert into the subtilisin active site. We show that TgMIC5 is an almost 50-fold more potent inhibitor of TgSUB1 activity than the small molecule inhibitor N-[N-(N-acetyl-L-leucyl)-L-leucyl]-L-norleucine (ALLN). Moreover, we demonstrate that TgMIC5 is retained on the parasite plasma membrane via its physical interaction with the membrane-anchored TgSUB1.
Organizational Affiliation:
Division of Molecular Biosciences, Imperial College London, South Kensington Campus, London SW7 2AZ, United Kingdom.
