Insect tolerance to the crystal toxins Cry1Ac and Cry2Ab is mediated by the binding of monomeric toxin to lipophorin glycolipids causing oligomerization and sequestration reactions

Ma, Gang, Rahman, Mahbubur M., Grant, Warwick, Schmidt, Otto and Asgari, Sassan (2012) Insect tolerance to the crystal toxins Cry1Ac and Cry2Ab is mediated by the binding of monomeric toxin to lipophorin glycolipids causing oligomerization and sequestration reactions. Developmental and Comparative Immunology, 37 1: 184-192. doi:10.1016/j.dci.2011.08.017


Author Ma, Gang
Rahman, Mahbubur M.
Grant, Warwick
Schmidt, Otto
Asgari, Sassan
Title Insect tolerance to the crystal toxins Cry1Ac and Cry2Ab is mediated by the binding of monomeric toxin to lipophorin glycolipids causing oligomerization and sequestration reactions
Journal name Developmental and Comparative Immunology   Check publisher's open access policy
ISSN 0145-305X
1879-0089
Publication date 2012-05-01
Year available 2011
Sub-type Article (original research)
DOI 10.1016/j.dci.2011.08.017
Volume 37
Issue 1
Start page 184
End page 192
Total pages 9
Place of publication Oxford, United Kingdom
Publisher Pergamon
Collection year 2012
Language eng
Abstract Endotoxins from the soil bacterium Bacillus thuringiensis are used worldwide to control insect pests and 28 vectors of diseases. Despite extensive use of the toxins as sprays and in transgenic crops, their mode of 29 action is still not completely known. Here we show that two crystal toxins binding to different glycopro- 30 tein receptors have similar glycolipid binding properties. The glycolipid binding domain was identified in 31 a recombinant peptide representing the domain II of the crystal toxin Cry1Ac (M-peptide). The recombi- 32 nant M-peptide was isolated from bacterial lysates as a mixture of monomers and dimers and formed 33 tetramers upon binding to glycolipid microvesicles from gut tissues and lipid particles from hemolymph 34 plasma. Likewise, when mature toxins and M-peptides where mixed with plasma, these peptides bind to 35 lipid particles and can be separated with lipophorin particles on low-density gradients. When mature 36 toxin and M-peptides are added to lipid particles in increasing amounts, the peptide-particle complexes 37 form higher aggregates that are similar to aggregates formed in low-density gradients in the presence of 38 the toxin. This could indicate that glycolipids on lipid particles are possible targets for toxin monomers in 39 the gut lumen, which upon binding to the glycolipids form tetramers and aggregate particles and thereby 40 sequester the toxin inside the gut lumen before it can interact with receptors on the brush border mem- 41 brane. The implication is that domain II interacting with glycolipids mediate tolerance to the toxin that is 42 separate from interaction of the toxin with glycoprotein receptors causing toxicity.
Keyword Bacillus thuringiensis
Cry1Ac
Cry2Ab
Glycolipid
Oligomerization
Lipophorin
Coagulation
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ
Additional Notes Available online 8 September 2011.

Document type: Journal Article
Sub-type: Article (original research)
Collections: Official 2012 Collection
School of Biological Sciences Publications
 
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Created: Thu, 08 Dec 2011, 02:10:34 EST by Gail Walter on behalf of School of Biological Sciences