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Giardia intestinalis cystatin is a potent inhibitor of papain, parasite cysteine proteases and, to a lesser extent, human cathepsin B
Author(s) -
Liu Jingyi,
Svärd Staffan G.,
Klotz Christian
Publication year - 2019
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 - 10.1002/1873-3468.13433
Subject(s) - proteases , cystatin , cysteine protease , papain , cysteine , cathepsin b , biochemistry , biology , cysteine proteinase inhibitors , cathepsin c , cathepsin , parasite hosting , protease , protease inhibitor (pharmacology) , giardia , cystatin c , microbiology and biotechnology , enzyme , virology , virus , apoptosis , programmed cell death , renal function , world wide web , computer science , antiretroviral therapy , viral load , caspase
Cystatins are important regulators of papain‐like cysteine proteases. In the protozoan parasite Giardia intestinalis , papain‐like cysteine proteases play an essential role in the parasite's biology and pathogenicity. Here, we characterized a cysteine protease inhibitor of G. intestinalis that belongs to type‐I‐cystatins. The parasite cystatin is shown to be a strong inhibitor of papain ( K i ≈ 0.3 n m ) and three parasite cysteine proteases ( CP 14019, CP 16160 and CP 16779, K i ≈ 0.9–5.8 n m ), but a weaker inhibitor of human cathepsin B ( K i ≈ 79.9 n m ). The protein localizes mainly in the cytoplasm. Together, these data suggest that cystatin of G. intestinalis plays a role in the regulation of cysteine protease activities in the parasite and, possibly, in the interaction with the host.