Cadherin‐like receptor binding facilitates proteolytic cleavage of helix α‐1 in domain I and oligomer pre‐pore formation of Bacillus thuringiensis Cry1Ab toxin
Open Access
- 1 February 2002
- journal article
- Published by Wiley in FEBS Letters
- Vol. 513 (2-3) , 242-246
- https://doi.org/10.1016/s0014-5793(02)02321-9
Abstract
Cry toxins form lytic pores in the insect midgut cells. The role of receptor interaction in the process of protoxin activation was analyzed. Incubation of Cry1Ab protoxin with a single chain antibody that mimics the cadherin‐like receptor and treatment with Manduca sexta midgut juice or trypsin, resulted in toxin preparations with high pore‐forming activity in vitro. This activity correlates with the formation of a 250 kDa oligomer that lacks the helix α‐1 of domain I. The oligomer, in contrast with the 60 kDa monomer, was capable of membrane insertion as judged by 8‐anilino‐1‐naphthalenesulfonate binding. Cry1Ab protoxin was also activated to a 250 kDa oligomer by incubation with brush border membrane vesicles, presumably by the action of a membrane‐associated protease. Finally, a model where receptor binding allows the efficient cleavage of α‐1 and formation of a pre‐pore oligomeric structure that is efficient in pore formation, is presented.Keywords
This publication has 36 references indexed in Scilit:
- Identification of a Gene Associated with Bt Resistance in Heliothis virescensScience, 2001
- Role of Proteolysis in Determining Potency of Bacillus thuringiensis Cry1Ac δ-EndotoxinApplied and Environmental Microbiology, 2000
- Evidence for intermolecular interaction as a necessary step for pore-formation activity and toxicity ofBacillus thuringiensisCry1Ab toxinFEMS Microbiology Letters, 2000
- Bacillus thuringiensisCrylA(a) Insecticidal Toxin: Crystal Structure and Channel FormationJournal of Molecular Biology, 1995
- Identification, Isolation, and Cloning of a Bacillus thuringiensis CryIAc Toxin-binding Protein from the Midgut of the Lepidopteran Insect Heliothis virescensPublished by Elsevier ,1995
- Bacillus thuringiensis CryIA(c) δ-endotoxin binding aminopeptidase in the Manduca sexta midgut has a glycosyl-phosphatidylinositol anchorInsect Biochemistry and Molecular Biology, 1995
- δ‐Endotoxins induce cation channels in Spodoptera frugiperda brush border membranes in suspension and in planar lipid bilayersFEBS Letters, 1995
- The receptor for Bacillus thuringiensis CrylA(c) delta‐endotoxin in the brush border membrane of the lepidopteran Manduca sexta is aminopeptidase NMolecular Microbiology, 1994
- Oligomerization of the channel-forming toxin aerolysin precedes insertion into lipid bilayersBiochemistry, 1993
- The interaction of a naphthalene dye with apomyoglobin and apohemoglobinJournal of Molecular Biology, 1965