Characterization of protein-ligand interactions by high-resolution solid-state NMR spectroscopy.
A novel approach for detection of ligand binding to a protein in solid samples is described. Hydrated precipitates of the anti-apoptotic protein Bcl-xL show well-resolved (13)C-(13)C 2D solid-state NMR spectra that allow site-specific assignment of resonances for many residues in uniformly (13)C-enriched samples. Binding of a small peptide or drug-like organic molecule leads to changes in the chemical shift of resonances from multiple residues in the protein that can be monitored to characterize binding. Differential chemical shifts can be used to distinguish between direct protein-ligand contacts and small conformational changes of the protein induced by ligand binding. The agreement with prior solution-state NMR results indicates that the binding pocket in solid and liquid samples is similar for this protein. Advantages of different labeling schemes involving selective (13)C enrichment of methyl groups of Ala, Val, Leu, and Ile (Cdelta1) for characterizing protein-ligand interactions are also discussed. It is demonstrated that high-resolution solid-state NMR spectroscopy on uniformly or extensively (13)C-enriched samples has the potential to screen proteins of moderate size ( approximately 20 kDa) for ligand binding as hydrated solids. The results presented here suggest the possibility of using solid-state NMR to study ligand binding in proteins not amenable to solution NMR.
Zech
Stephan G
SG
Department of Chemistry, Columbia University, New York, New York 10027, USA.
Olejniczak
Edward
E
Hajduk
Philip
P
Mack
Jamey
J
McDermott
Ann E
AE
D001665:Binding Sites; D002247:Carbon Isotopes; D008024:Ligands; D009587:Nitrogen Isotopes; D019906:Nuclear Magnetic Resonance, Biomolecular / Q000379:methods*; D011487:Protein Conformation; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000737:chemistry* / Q000378:metabolism; D015203:Reproducibility of Results; D051020:bcl-X Protein
D002247:Carbon Isotopes; D008024:Ligands; D009587:Nitrogen Isotopes; D019253:Proto-Oncogene Proteins c-bcl-2; D051020:bcl-X Protein