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The proregion of papaya proteinase IV inhibits Colorado potato beetle digestive cysteine proteinases
Author(s) -
Visal Savita,
Taylor Mark A.J.,
Michaud Dominique
Publication year - 1998
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/s0014-5793(98)01018-7
Subject(s) - pepstatin , biochemistry , proteases , colorado potato beetle , proteolysis , cysteine protease , cathepsin , protease , biology , protease inhibitor (pharmacology) , cysteine proteinase inhibitors , cysteine , cystatin , enzyme , botany , pest analysis , antiretroviral therapy , human immunodeficiency virus (hiv) , renal function , viral load , immunology , cystatin c , apoptosis , caspase , programmed cell death
Three distinct digestive protease systems were induced in larvae of the herbivorous pest, Colorado potato beetle (CPB; Leptinotarsa decemlineata Say), and used as a model to assess the ability of the proregion of papaya proteinase IV (PPIV; glycyl endopeptidase, EC 3.4.22.25) to act as an inhibitor of insect digestive cysteine proteinases. As shown by gelatin/PAGE and complementary inhibition assays, a recombinant form of the proregion produced in Escherichia coli inhibited a fraction of the insect proteases also inhibited by the well‐characterized inhibitor of cysteine proteinases, oryzacystatin I (OCI). In contrast with OCI, the inhibitory potency of the proregion was affected by an increase of the temperature, suggesting a certain alteration of its structural integrity by the insect non‐target proteases. This apparent susceptibility to proteolysis was confirmed by SDS‐PAGE, after challenging the proregion with the different insect extracts. As seen on gel, selective inhibition of the insect aspartate proteinase, cathepsin D, with the inhibitor pepstatin A preserved the activity of the proregion against cysteine proteinases by preventing its hydrolysis. Taken together, these observations suggest the potential of plant protease proregions as regulators of cysteine proteinases in biotechnological systems, and show the ability of protease inhibitors to preserve the integrity of ‘companion’ defense‐related proteins from the action of insensitive proteases in target pests.