NMR line shapes and multi-state binding equilibria
Abstract Biological function of proteins relies on conformational transitions and binding of specific ligands. Proteinā??ligand interactions are thermodynamically and kinetically coupled to conformational changes in protein structures as conceptualized by the models of pre-existing equilibria and induced fit. NMR spectroscopy is particularly sensitive to complex ligand-binding modesā??NMR line-shape analysis can provide for thermodynamic and kinetic constants of ligand-binding equilibria with the site-specific resolution. However, broad use of line shape analysis is hampered by complexity of NMR line shapes in multi-state systems. To facilitate interpretation of such spectral patterns, I computationally explored systems where isomerization or dimerization of a protein (receptor) molecule is coupled to binding of a ligand. Through an extensive analysis of multiple exchange regimes for a family of three-state models, I identified signature features to guide an NMR experimentalist in recognizing specific interaction mechanisms. Results show that distinct multi-state models may produce very similar spectral patterns. I also discussed aggregation of a receptor as a possible source of spurious three-state line shapes and provided specific suggestions for complementary experiments that can ensure reliable mechanistic insight.
- Content Type Journal Article
- Category Article
- Pages 1-14
- DOI 10.1007/s10858-012-9636-3
- Authors
- Evgenii L. Kovrigin, Department of Chemistry, Marquette University, PO Box 1881, Milwaukee, WI 53201, USA
Source: Journal of Biomolecular NMR