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Identification and characterization of a novel factor XIIa inhibitor in the hematophagous insect, Triatoma infestans (Hemiptera: Reduviidae)
Author(s) -
Campos Ivan T.N.,
Tanaka-Azevedo Anita M.,
Tanaka Aparecida S.
Publication year - 2004
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/j.febslet.2004.10.052
Subject(s) - triatoma infestans , reduviidae , midgut , biology , triatoma , factor xii , thrombin , serine protease , microbiology and biotechnology , protease , biochemistry , coagulation , hemiptera , trypanosoma cruzi , immunology , medicine , enzyme , zoology , ecology , platelet , parasite hosting , world wide web , computer science , larva
Recently, we have cloned several Kazal‐type serine protease inhibitors from the midgut of the Triatoma infestans bug. A single gene composed of multi Kazal‐type domains, in tandem, encodes these inhibitors. In this work, we describe the purification and characterization of recombinant infestins 3‐4 and 4, which are potent factor XIIa inhibitors ( K i =67 pM and 128 pM, respectively). We also identified the first native factor XIIa inhibitor from a hematophagous insect. The factor XIIa inhibitory activity of infestin 4 demonstrates extremely efficient anticoagulant activity, prolonging activated partial thromboplastin time by approximately 3 times. Our results suggest that infestins perform a very important role in the T. infestans midgut during meal acquisition and digestion by controlling blood coagulation by means of inhibiting thrombin and factor XIIa.