Insecticidal Toxin Complex Proteins from Xenorhabdus nematophilus

Toxin complexes from Xenorhabdus and Photorhabdus spp. bacteria represent novel insecticidal proteins. We purified a native toxin complex (toxin complex 1) from Xenorhabdus nematophilus. The toxin complex is composed of three different proteins, XptA2, XptB1, and XptC1, representing products from cl...

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Published inThe Journal of biological chemistry Vol. 286; no. 26; pp. 22742 - 22749
Main Authors Sheets, Joel J., Hey, Tim D., Fencil, Kristin J., Burton, Stephanie L., Ni, Weiting, Lang, Alexander E., Benz, Roland, Aktories, Klaus
Format Journal Article
LanguageEnglish
Published Elsevier Inc 01.07.2011
Subjects
Insect
Membrane Bilayer
Protein Assembly
Protein Self-assembly
Protein-Protein Interactions
Receptors
Toxins
Protein Self-assembly
Receptors
Membrane Bilayer
Toxins
Insect
Protein Assembly
Protein-Protein Interactions
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Summary:Toxin complexes from Xenorhabdus and Photorhabdus spp. bacteria represent novel insecticidal proteins. We purified a native toxin complex (toxin complex 1) from Xenorhabdus nematophilus. The toxin complex is composed of three different proteins, XptA2, XptB1, and XptC1, representing products from class A, B, and C toxin complex genes, respectively. We showed that recombinant XptA2 and co-produced recombinant XptB1 and XptC1 bind together with a 4:1:1 stoichiometry. XptA2 forms a tetramer of ∼1,120 kDa that bound to solubilized insect brush border membranes and induced pore formation in black lipid membranes. Co-expressed XptB1 and XptC1 form a tight 1:1 binary complex where XptC1 is C-terminally truncated, resulting in a 77-kDa protein. The ∼30-kDa C-terminally cleaved portion of XptC1 apparently only loosely associates with this binary complex. XptA2 had only modest oral toxicity against lepidopteran insects but as a complex with co-produced XptB1 and XptC1 had high levels of insecticidal activity. Addition of co-expressed class B (TcdB2) and class C (TccC3) proteins from Photorhabdus luminescens to the Xenorhabdus XptA2 protein resulted in formation of a hybrid toxin complex protein with the same 4:1:1 stoichiometry as the native Xenorhabdus toxin complex 1. This hybrid toxin complex, like the native toxin complex, was highly active against insects.
ISSN:0021-9258
1083-351X
DOI:10.1074/jbc.M111.227009