3EB7

Crystal Structure of Insecticidal Delta-Endotoxin Cry8Ea1 from Bacillus Thuringiensis at 2.2 Angstroms Resolution

Replaces:  2QKG

Summary for 3EB7

• Entry DOI: 10.2210/pdb3eb7/pdb
• Descriptor: Insecticidal Delta-Endotoxin Cry8Ea1, SULFATE ION, ACETATE ION, ... (4 entities in total)
• Functional Keywords: endotoxin, cry8e, bacillus thuringiensis, toxin
• Biological source: Bacillus Thuringiensis
• Total number of polymer chains: 3
• Total formula weight: 200311.91

Authors

Guo, S.,Ye, S.,Song, F.,Zhang, J.,Wei, L.,Shu, C.L. (deposition date: 2008-08-27, release date: 2008-09-16, Last modification date: 2023-11-01)

Primary citation

Guo, S.,Ye, S.,Liu, Y.,Wei, L.,Xue, J.,Wu, H.,Song, F.,Zhang, J.,Wu, X.,Huang, D.,Rao, Z.
Crystal structure of Bacillus thuringiensis Cry8Ea1: An insecticidal toxin toxic to underground pests, the larvae of Holotrichia parallela.
J.Struct.Biol., 168:259-266, 2009

PubMed Abstract: Crystal (Cry) proteins belong to an insect toxin family encoded and expressed by a variety of Bacillus thuringiensis isolates, and are named due to their in vivo auto-crystallization abilities. To kill the infected host insects, protease-activated Cry toxins should firstly be recognized by certain membrane receptors on the surface of insect midgut epithelial cells and consequently assemble together as lethal transmembrane pores. Here we report the 2.2-A crystal structure of Cry8Ea1 toxin, a Cry family member specifically toxic to the underground larvae of Holotrichia parallela. Superimposition of the domain I from Cry8Ea1 and other structurally characterized Cry toxins reveals an identical surface proline residue and a highly conserved kink of a helix, both of which have drawn comparatively little attention from previous researchers. Further structural analysis and functional studies suggest that both the proline and the helix kink might be essential in exposing a helix-helix hairpin, which is believed to be the very first step in the well-known "umbrella" model of the membrane penetration. In summary, we propose a plausible model of the initiation of Cry toxin domain I disassembly before membrane penetration and pore formation.

PubMed: 19591941
DOI: 10.1016/j.jsb.2009.07.004

Experimental method

X-RAY DIFFRACTION (2.3 Å)