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The three‐dimensional structure of notexin, a presynaptic neurotoxic phospholipase A 2 at 2.0 Å resolution
Author(s) -
Westerlund Bengt,
Nordlund Pär,
Uhlin Ulla,
Eaker David,
Eklund Hans
Publication year - 1992
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(92)81238-h
Subject(s) - chemistry , phospholipase a2 , molecule , phospholipase a , residue (chemistry) , phospholipase , crystallography , molecular replacement , enzyme , protein structure , stereochemistry , biophysics , biochemistry , biology , organic chemistry
The three‐dimensional structure of notexin has been solved by molecular replacement methods. The structure has been refined at 2.0 Å resolution to a crystallographic R‐value of 16.5% with good stereo‐chemistry. The core of the protein is very similar to other phospholipase A 2 s (PLA 2 s) but several parts of the molecule are distinctly different. The most significant differences from PLA 2 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 PLA 2 s. The Cα positions for residues 86–88 differ by about 6 Å from both the bovine and the rattlesnake enzyme. The crystals contain no Ca 2+ ions. Instead, a water molecule occupies the calcium site.