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Novel insights on the mechanism of action of α‐amylase inhibitors from the plant defensin family
Author(s) -
Pelegrini Patrícia B.,
Lay Fung T.,
Murad André M.,
Anderson Marilyn A.,
Franco Octavio L.
Publication year - 2008
Publication title -
proteins: structure, function, and bioinformatics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.699
H-Index - 191
eISSN - 1097-0134
pISSN - 0887-3585
DOI - 10.1002/prot.22086
Subject(s) - vigna , biology , defensin , callosobruchus maculatus , enzyme , biochemistry , heterologous expression , botany , gene , pest analysis , recombinant dna
Plant defensins are small cysteine‐rich proteins commonly synthesized in plants, encoded by large multigene families. Most plant defensins that have been characterized to date show potent antifungal and/or bactericidal activities. This report describes VuD1, an unusual defensin that is able to inhibit insect‐pest α‐amylases. VuD1 was cloned from cowpea ( Vigna unguiculata ) seeds and expressed in a heterologous system. Inhibitory enzyme assays showed that VuD1 efficiently inhibits α‐amylases from the weevils Acanthoscelides obtectus and Zabrotes subfasciatus , caused low inhibition toward mammalian enzymes and was unable to inhibit the α‐amylases from Callosobruchus maculatus and Aspergillus fumigatus . To shed some light over the mechanism of action of VuD1, molecular modeling analyses were performed, revealing that the N‐terminus of the molecule is responsible for binding with the active site of weevil enzymes. Moreover, models of VuD1 and mammalian enzymes were also generated to elucidate the specificity mechanisms. The data presented herein suggests that this defensin has potential application in the development of transgenic plants for insect pest control. Proteins 2008. © 2008 Wiley‐Liss, Inc.