Cry34Ab1 is one member of a binary Bacillus thuringiensis (Bt) crystal protein set isolated from Bt strain PS149B1.[1] The protein exists as a 14 kDa aegerolysin that, in presence of Cry35Ab1, exhibits insecticidal activity towards Western Corn Rootworm. [1][2] The protein has been transformed into maize plants under the commercialized events 4114 (DP-ØØ4114-3) by Pioneer Hi-Bred and 59122 (DAS-59122-7) by Dow AgroSciences. These events have, in turn, been bred into multiple trait stacks in additional products.

13.6 kDa insecticidal crystal protein
Identifiers
OrganismBacillus thuringiensis
SymbolCry34Ab1
UniProtQ939T0
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StructuresSwiss-model
DomainsInterPro
43.8 kDa insecticidal crystal protein
Identifiers
OrganismBacillus thuringiensis
SymbolCry35Ab1
UniProtQ939S9
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StructuresSwiss-model
DomainsInterPro

Cry34/35Ab1 binary toxins bind to the insect's brush border membrane vesicles (BBMVs) of cells in the epithelial lining of midgut, where they form pores; this leads to necrosis and, eventually, the insect's death.[3] The Cry35Ab1 (45 kDa) protein does not convey specificity in the absence of Cry34Ab1, indicating that the smaller 14 kDa Cry34Ab1 protein is critical for BBMV binding and recruitment of Cry35Ab1 to induce insecticidal effect.[2]

Cry34Ab1 is unrelated to Bt delta-endotoxins. It is an aegerolysin (Pfam PF06355) composed of two beta sheets in a beta-sandwich structure; the total protein is composed of 117 amino acid residues and contains a hydrophobic core.[4] Its family placement shows that interaction with cell membranes is consistent with its role in the binary Cry34Ab1/Cry35Ab1 toxin complex.[4] The partner toxin, Cry35Ab1, is a prototypical member of its own group (Pfam PF05431). Its structure is similar to that of aerolysin, Cry45Aa1, and Cry46Aa1.[4]

References

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  1. ^ a b Moellenbeck DJ, Peters ML, Bing JW, Rouse JR, Higgins LS, Sims L, et al. (July 2001). "Insecticidal proteins from Bacillus thuringiensis protect corn from corn rootworms". Nature Biotechnology. 19 (7): 668–72. doi:10.1038/90282. PMID 11433280. S2CID 18133775.
  2. ^ a b Li H, Olson M, Lin G, Hey T, Tan SY, Narva KE (2013-01-04). "Bacillus thuringiensis Cry34Ab1/Cry35Ab1 interactions with western corn rootworm midgut membrane binding sites". PLOS ONE. 8 (1): e53079. Bibcode:2013PLoSO...853079L. doi:10.1371/journal.pone.0053079. PMC 3537739. PMID 23308139.
  3. ^ Palma L, Muñoz D, Berry C, Murillo J, Caballero P (December 2014). "Bacillus thuringiensis toxins: an overview of their biocidal activity". Toxins. 6 (12): 3296–325. doi:10.3390/toxins6123296. PMC 4280536. PMID 25514092.
  4. ^ a b c Kelker MS, Berry C, Evans SL, Pai R, McCaskill DG, Wang NX, et al. (2014-11-12). "Structural and biophysical characterization of Bacillus thuringiensis insecticidal proteins Cry34Ab1 and Cry35Ab1". PLOS ONE. 9 (11): e112555. Bibcode:2014PLoSO...9k2555K. doi:10.1371/journal.pone.0112555. PMC 4229197. PMID 25390338.