The crystal structure of diphtheria toxin

Nature. 1992 May 21;357(6375):216-22. doi: 10.1038/357216a0.


The crystal structure of the diphtheria toxin dimer at 2.5 A resolution reveals a Y-shaped molecule of three domains. The catalytic domain, called fragment A, is of the alpha + beta type. Fragment B actually consists of two domains. The transmembrane domain consists of nine alpha-helices, two pairs of which are unusually apolar and may participate in pH-triggered membrane insertion and translocation. The receptor-binding domain is a flattened beta-barrel with a jelly-roll-like topology. Three distinct functions of the toxin, each carried out by a separate structural domain, can be useful in designing chimaeric proteins, such as immunotoxins, in which the receptor-binding domain is substituted with antibodies to target other cell types.

Publication types

  • Comparative Study
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Bacterial Toxins / chemistry
  • Binding Sites
  • Computer Simulation
  • Diphtheria Toxin / chemistry*
  • Immunoglobulin Variable Region / chemistry
  • Models, Molecular
  • Protein Conformation
  • Software
  • Thermodynamics
  • X-Ray Diffraction


  • Bacterial Toxins
  • Diphtheria Toxin
  • Immunoglobulin Variable Region