Delta endotoxin

delta endotoxin, N-terminal domain
crystal structure of the insecticidal bacterial del endotoxin Cry3Bb1 bacillus thuringiensis
Identifiers
Symbol	Endotoxin_N
Pfam	PF03945
InterPro	IPR005639
SCOP	1dlc
SUPERFAMILY	1dlc
TCDB	1.C.2
Available protein structures: Pfam structures PDB RCSB PDB; PDBe; PDBj PDBsum structure summary

delta endotoxin
Structure of insecticidal delta-endotoxin from Bacillus thuringiensis.[1]
Identifiers
Symbol	Endotoxin_M
Pfam	PF00555
InterPro	IPR015790
SCOP	1dlc
SUPERFAMILY	1dlc
TCDB	1.C.2
OPM superfamily	95
OPM protein	1w99
Available protein structures: Pfam structures PDB RCSB PDB; PDBe; PDBj PDBsum structure summary

Bacillus thuringiensis delta-Endotoxin, middle domain
insecticidal crystal protein cry2aa
Identifiers
Symbol	Endotoxin_mid
Pfam	PF09131
InterPro	IPR015214
SCOP	1i5p
SUPERFAMILY	1i5p
Available protein structures: Pfam structures PDB RCSB PDB; PDBe; PDBj PDBsum structure summary

delta endotoxin
insecticidal crystal protein cry2aa
Identifiers
Symbol	Endotoxin_C
Pfam	PF03944
Pfam clan	CL0202
InterPro	IPR005638
SCOP	1dlc
SUPERFAMILY	1dlc
TCDB	1.C.2
CDD	cd04085
Available protein structures: Pfam structures PDB RCSB PDB; PDBe; PDBj PDBsum structure summary

Delta endotoxins (δ-endotoxins, also called Cry and Cyt toxins) are pore-forming toxins produced by Bacillus thuringiensis species of bacteria. They are useful for their insecticidal action.

During spore formation the bacteria produce crystals of this protein. When an insect ingests these proteins, they are activated by proteolytic cleavage. The N-terminus is cleaved in all of the proteins and a C-terminal extension is cleaved in some members. Once activated, the endotoxin binds to the gut epithelium and causes cell lysis by the formation of cation-selective channels, which leads to death. The activated region of the delta toxin is composed of three distinct structural domains: an N-terminal helical bundle domain (InterPro: IPR005639) involved in membrane insertion and pore formation; a beta-sheet central domain involved in receptor binding; and a C-terminal beta-sandwich domain (InterPro: IPR005638) that interacts with the N-terminal domain to form a channel.^[2][3][4][5]

References

1. Li JD, Carroll J, Ellar DJ (October 1991). "Crystal structure of insecticidal delta-endotoxin from Bacillus thuringiensis at 2.5 A resolution". Nature. 353 (6347): 815–21. doi:10.1038/353815a0. PMID 1658659.
2. Cygler M, Borisova S, Grochulski P, Masson L, Pusztai-carey M, Schwartz JL, Brousseau R (1995). "Bacillus thuringiensis CryIA(a) insecticidal toxin: crystal structure and channel formation". J. Mol. Biol. 254 (3): 447–464. doi:10.1006/jmbi.1995.0630. PMID 7490762.
3. Ghosh D, Pangborn W, Galitsky N, Cody V, Wojtczak A, Luft JR, English L (2001). "Structure of the insecticidal bacterial delta-endotoxinCry3Bb1 of Bacillus thuringiensis". Acta Crystallogr. D. 57 (8): 1101–1109. doi:10.1107/S0907444901008186. PMID 11468393.
4. Grochulski P, Masson L, Borisova S, Pusztai-Carey M, Schwartz JL, Brousseau R, Cygler M (December 1995). "Bacillus thuringiensis CryIA(a) insecticidal toxin: crystal structure and channel formation". J. Mol. Biol. 254 (3): 447–64. doi:10.1006/jmbi.1995.0630. PMID 7490762.
5. Galitsky N, Cody V, Wojtczak A, Ghosh D, Luft JR, Pangborn W, English L (August 2001). "Structure of the insecticidal bacterial delta-endotoxin Cry3Bb1 of Bacillus thuringiensis". Acta Crystallogr. D. 57 (Pt 8): 1101–9. doi:10.1107/S0907444901008186. PMID 11468393.

Further reading

• Bravo, A.; Gill, S. S.; Soberón, M. (2007). "Mode of action of Bacillus thuringiensis Cry and Cyt toxins and their potential for insect control". Toxicon. 49 (4): 423–435. doi:10.1016/j.toxicon.2006.11.022. PMC 1857359. PMID 17198720.
• Pigott, C. R.; Ellar, D. J. (2007). "Role of Receptors in Bacillus thuringiensis Crystal Toxin Activity" (PDF). Microbiology and Molecular Biology Reviews. 71 (2): 255–281. doi:10.1128/MMBR.00034-06. PMC 1899880. PMID 17554045.

This article incorporates text from the public domain Pfam and InterPro IPR015790