The three-dimensional structure of notexin, a presynaptic neurotoxic phospholipase A2 at 2.0 A resolution

FEBS Lett. 1992 Apr 20;301(2):159-64. doi: 10.1016/0014-5793(92)81238-h.


The three-dimensional structure of notexin has been solved by molecular replacement methods. The structure has been refined at 2.0 A resolution to a crystallographic R-value of 16.5% with good stereo-chemistry. The core of the protein is very similar to other phospholipase A2s (PLA2 s) but several parts of the molecule are distinctly different. The most significant differences from PLA2 s from bovine pancreas and rattlesnake occur in the stretches 56-80 and 85-89. Residue 69, which has been shown to be important for phospholipase binding, has a different conformation and different interactions than in other known PLA2s. The C alpha positions for residues 86-88 differ by about 6 A from both the bovine and the rattlesnake enzyme. The crystals contain no Ca2+ ions. Instead, a water molecule occupies the calcium site.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Cattle
  • Computer Simulation
  • Elapid Venoms / chemistry*
  • Elapid Venoms / genetics
  • Models, Molecular
  • Molecular Sequence Data
  • Mutagenesis, Site-Directed
  • Neurotoxins / chemistry*
  • Neurotoxins / genetics
  • Phospholipases A / chemistry*
  • Phospholipases A / genetics
  • Phospholipases A2
  • Protein Conformation
  • Sequence Alignment
  • Snakes
  • X-Ray Diffraction


  • Elapid Venoms
  • Neurotoxins
  • notexin
  • Phospholipases A
  • Phospholipases A2