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

Experimental Data Snapshot

  • Resolution: 2.30 Å
  • R-Value Free: 0.230 
  • R-Value Work: 0.162 
  • R-Value Observed: 0.169 

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Crystal structure of Bacillus thuringiensis Cry8Ea1: An insecticidal toxin toxic to underground pests, the larvae of Holotrichia parallela.

Guo, S.Ye, S.Liu, Y.Wei, L.Xue, J.Wu, H.Song, F.Zhang, J.Wu, X.Huang, D.Rao, Z.

(2009) J Struct Biol 168: 259-266

  • DOI: https://doi.org/10.1016/j.jsb.2009.07.004
  • Primary Citation of Related Structures:  

  • 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.

  • Organizational Affiliation

    Beijing Institute of Technology, China. guosy@bit.edu.cn

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Insecticidal Delta-Endotoxin Cry8Ea1
A, B, C
589Bacillus thuringiensisMutation(s): 0 
Gene Names: cry8Ea1
Find proteins for B3LEP7 (Bacillus thuringiensis)
Explore B3LEP7 
Go to UniProtKB:  B3LEP7
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupB3LEP7
Sequence Annotations
  • Reference Sequence
Small Molecules
Ligands 2 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
Query on SO4

Download Ideal Coordinates CCD File 
D [auth A]
E [auth A]
G [auth B]
H [auth B]
I [auth B]
D [auth A],
E [auth A],
G [auth B],
H [auth B],
I [auth B],
J [auth B],
K [auth B],
L [auth B],
M [auth B],
O [auth C],
P [auth C],
Q [auth C],
R [auth C]
O4 S
Query on ACT

Download Ideal Coordinates CCD File 
F [auth A],
N [auth B],
S [auth C]
C2 H3 O2
Experimental Data & Validation

Experimental Data

  • Resolution: 2.30 Å
  • R-Value Free: 0.230 
  • R-Value Work: 0.162 
  • R-Value Observed: 0.169 
  • Space Group: C 1 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 407.282α = 90
b = 47.956β = 91.12
c = 103.121γ = 90
Software Package:
Software NamePurpose
ADSCdata collection
HKL-2000data reduction
HKL-2000data scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2008-09-16
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Derived calculations, Version format compliance
  • Version 1.2: 2023-11-01
    Changes: Data collection, Database references, Derived calculations, Refinement description