ISSN:
1573-5001
Keywords:
cross-correlated relaxation
;
CSA
;
isotope shifts
;
ψ angle
;
structural quality
;
structure calculation
;
structure refinement
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Chemistry and Pharmacology
Notes:
Abstract Cross-correlated relaxation rates involving the Cα-Hα dipolar interaction and the carbonyl (C′) chemical shift anisotropy (CSA) have been measured using two complementary 3D experiments. We show that the protein backbone angle ψ can be directly refined against such cross-correlated relaxation rates (ΓHα Cα,C′) and the three-bond H/D isotope effect on the Cα chemical shifts (3ΔCα (ND)). By simultaneously using both experimental parameters as restraints during NMR structure calculations, a unique value for the backbone angle ψ is defined. We have applied the new refinement method to the α-Spectrin SH3 domain (a β-sheet protein) and to the Sgs1p HRDC domain (an α-helical protein) and show that the quality of the NMR structures is substantially improved, judging from the atomic coordinate precision and the Ramachandran map. In addition, the ψ-refined NMR structures of the SH3 domain deviate less from the 1.8 Å crystal structure, suggesting an improved accuracy. The proposed refinement method can be used to significantly improve the quality of NMR structures and will be applicable to larger proteins.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1008344715812
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