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The influence of stereospecific assignments on the determination of three‐dimensional structures of proteins by nuclear magnetic resonance spectroscopy
Author(s) -
Driscoll Paul C.,
Gronenborn Angela M.,
Clore G.Marius
Publication year - 1989
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(89)80134-6
Subject(s) - nuclear magnetic resonance spectroscopy , nuclear magnetic resonance , stereospecificity , spectroscopy , chemistry , physics , biochemistry , quantum mechanics , catalysis
The influence of the stereospecific assignments of β‐methylene protons and the classification of χ 1 torsion angles on the definition of the three‐dimensional structures of proteins determined from NMR data is investigated using the sea anemone protein BDS‐I (43 residues) as a model system. Two sets of structures are computed. The first set comprises 42 converged structures (denoted STEREO structures) calculated on the basis of the complete list of restraints derived from the NMR data, consisting of 489 interproton and 24 hydrogen bonding distance restraints, supplemented by 23 ϕ backbone and 21 χ 1 side chain torsion angle restraints. The second set comprises 31 converged structures (denoted NOSTEREO structures) calculated from a reduced data set in which those restraints arising from stereospecific assignments, and the corresponding χ 1 torsion angle restraints, are explicitly omitted. The results show that the inclusion of the stereospecific restraints leads to a significant improvement in the definition of the structure of BDS‐I, both with respect to the backbone and the detailed arrangement of the side chains. Average atomic rms differences between the individual structures and the mean structures for the backbone atoms are 0.67±0.12 Å and 0.93±0.16 Å for the STEREO and NOSTEREO structures, respectively; the corresponding values for all atoms are 0.90±0.17 Å and 1.17±0.17 Å, respectively. In addition, while the overall fold remains unchanged, there is a small but significant atomic displacement between the two sets of structures.