1bpi
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THE STRUCTURE OF BOVINE PANCREATIC TRYPSIN INHIBITOR AT 125K: DEFINITION OF CARBOXYL-TERMINAL RESIDUES GLYCINE-57 AND ALANINE-58
OverviewOverview
The structure of bovine pancreatic trypsin inhibitor has been refined to a, resolution of 1.1 A against data collected at 125 K. The space group of, the form II crystal is P2(1)2(1)2(1) with a = 75.39(3), b = 22.581(7), c =, 28.606 (9) A (cf. a = 74.1, b = 23.4, c = 28.9 A at room temperature). The, structure was refined by restrained least-squares minimization of, summation operator w(F (o)(2)- F (c)(2))(2) with the SHELXL93 program. As, the model improved, water molecules were included and exceptionally clear, electron density was found for two residues, Gly57 and Ala58, that had, been largely obscured at room temperature. The side chains of residues, Glu7 and Arg53 were modelled over two positions with refined occupancy, factors. The final model contains 145.6 water molecules distributed over, 167 sites, and a single phosphate group disordered over two sites. The, root-mean-square discrepancy between Calpha atoms in residues Arg1-Gly56, at room and low temperatures is 0.4 A. A comparison of models refined with, anisotropic and isotropic thermal parameters revealed that there were no, significant differences in atomic positions. The final weighted R-factor, on F(2) (wR(2)) for data in the range 10-1.1 A was 35.9% for the, anisotropic model and 40.9% for the isotropic model. Conventional, R-factors based on F for F > 4sigma(F) were 12.2 and 14.6%, respectively, corresponding to 16.1 and 18.7% on all data. These large R-factor, differences were not reflected in values of R(free), which were not, significantly different at 21.5(5) and 21.8(4)%, respectively. These, results, along with the relatively straightforward nature of the, refinement, clearly highlight the benefits of low-temperature data, collection.
About this StructureAbout this Structure
1BPI is a Single protein structure of sequence from Bos taurus with PO4 as ligand. Full crystallographic information is available from OCA.
ReferenceReference
Structure of bovine pancreatic trypsin inhibitor at 125 K definition of carboxyl-terminal residues Gly57 and Ala58., Parkin S, Rupp B, Hope H, Acta Crystallogr D Biol Crystallogr. 1996 Jan 1;52(Pt 1):18-29. PMID:15299722
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