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A short proregion of trialysin, a pore‐forming protein of Triatoma infestans salivary glands, controls activity by folding the N‐terminal lytic motif
Author(s) -
Martins Rafael M.,
Amino Rogerio,
Daghastanli Katia R.,
Cuccovia Iolanda M.,
Juliano Maria A.,
Schenkman Sergio
Publication year - 2008
Publication title -
the febs journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.981
H-Index - 204
eISSN - 1742-4658
pISSN - 1742-464X
DOI - 10.1111/j.1742-4658.2008.06260.x
Subject(s) - triatoma infestans , lytic cycle , biochemistry , peptide , saliva , biology , trypanosoma cruzi , proteolysis , triatominae , chagas disease , microbiology and biotechnology , reduviidae , hemiptera , parasite hosting , virology , virus , world wide web , computer science , enzyme , zoology
Triatoma infestans (Hemiptera: Reduviidae) is a hematophagous insect that transmits the protozoan parasite Trypanosoma cruzi , the etiological agent of Chagas’ disease. Its saliva contains trialysin, a protein that forms pores in membranes. Peptides based on the N‐terminus of trialysin lyse cells and fold into α‐helical amphipathic segments resembling antimicrobial peptides. Using a specific antiserum against trialysin, we show here that trialysin is synthesized as a precursor that is less active than the protein released after saliva secretion. A synthetic peptide flanked by a fluorophore and a quencher including the acidic proregion and the lytic N‐terminus of the protein is also less active against cells and liposomes, increasing activity upon proteolysis. Activation changes the peptide conformation as observed by fluorescence increase and CD spectroscopy. This mechanism of activation could provide a way to impair the toxic effects of trialysin inside the salivary glands, thus restricting damaging lytic activity to the bite site.