title: The three-dimensional structure of notexin, a presynaptic neurotoxic phospholipase A2 at 2.0 A resolution.
abstract: 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.
authors.affiliation: Department of Biochemistry, Uppsala University, Sweden.
authors.forename: B
authors.initials: B
authors.lastname: Westerlund
authors.forename: P
authors.initials: P
authors.lastname: Nordlund
authors.forename: U
authors.initials: U
authors.lastname: Uhlin
authors.forename: D
authors.initials: D
authors.lastname: Eaker
authors.forename: H
authors.initials: H
authors.lastname: Eklund
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002417:Cattle; D003198:Computer Simulation; D004546:Elapid Venoms / Q000737:chemistry* / Q000235:genetics; D008958:Models, Molecular; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009498:Neurotoxins / Q000737:chemistry* / Q000235:genetics; D010741:Phospholipases A / Q000737:chemistry* / Q000235:genetics; D054467:Phospholipases A2; D011487:Protein Conformation; D016415:Sequence Alignment; D012911:Snakes; D014961:X-Ray Diffraction
chemical_list: D004546:Elapid Venoms; D009498:Neurotoxins; C005082:notexin; D010741:Phospholipases A; D054467:Phospholipases A2