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Accuracy of bound peptide structures determined by exchange transferred nuclear Overhauser data: a simulation study.
E Z Eisenmesser1, A P Zabell, C B Post
1Department of Biological Sciences, Purdue University, West Lafayette, IN 47907-1333, USA.
Journal of Biomolecular NMR
|July 26, 2000
Summary
The exchange-transferred NOE (etNOE) method can determine peptide structures bound to proteins, even with limited data. Reliable structures are achievable when non-neighboring residue interactions span the entire peptide length.
Area of Science:
- Biophysics
- Structural Biology
- Drug Design
Background:
- The exchange-transferred NOE (etNOE) method is crucial for determining the 3D structure of peptides bound to macromolecules.
- Analyzing large or complex systems like membrane receptors is challenging with direct methods.
- etNOE relies on intramolecular NOE interactions within the ligand, but is limited by fewer observed NOEs per residue compared to direct protein structure determination.
Purpose of the Study:
- To investigate the conditions necessary for obtaining reliable structural information using the etNOE method.
- To assess the accuracy and precision of structures determined by etNOE under various conditions.
- To evaluate the impact of NOE interaction patterns on structural reliability.
Main Methods:
- Simulated etNOE data using the CORONA program.
- Incorporated magnetic relaxation and exchange rates into a rate-matrix.
- Utilized two peptide-protein complexes derived from a cAMP-dependent protein kinase and inhibitor peptide system.
Main Results:
- Reasonably accurate peptide structures can be determined with sparse NOE data, particularly when interactions are between non-neighboring residues.
- Structural reliability is indicated by the pattern of observed NOE interactions.
- High accuracy (approx. 1.3 Å rmsd for backbone) is achievable when etNOE interactions span the peptide length, though global precision (approx. 0.9 Å rmsd) is not correlated with accuracy.
Conclusions:
- The etNOE method is a valuable tool for peptide structure determination in macromolecular complexes.
- The distribution and density of NOE interactions significantly influence structural accuracy and reliability.
- Local backbone precision serves as a good indicator of local structural accuracy.