Discovery and characterization of cooperative ligand binding in the adaptive region of interleukin-2
Hyde, J., Braisted, A.C., Randal, M., Arkin, M.R.(2003) Biochemistry 42: 6475-6483
- PubMed: 12767230 
- DOI: https://doi.org/10.1021/bi034138g
- Primary Citation of Related Structures:  
1NBP - PubMed Abstract: 
The cytokine hormone interleukin-2 (IL-2) contains a highly adaptive region that binds small, druglike molecules. The binding properties of this adaptive region have been explored using a "tethering" method that relies on the formation of a disulfide bond between the protein and small-molecule ligands. Using tethering, surface plasmon resonance (SPR), and X-ray crystallography, we have discovered that the IL-2 adaptive region contains at least two cooperative binding sites where the binding of a first ligand to one site promotes or antagonizes the binding of a second ligand to the second site. Cooperative energies of interaction of -2 kcal/mol are observed. The observation that the adaptive region contains two adjacent sites may lead to the development of tight-binding antagonists of a protein-protein interaction. Cooperative ligand binding in the adaptive region of IL-2 underscores the importance of protein dynamics in molecular recognition. The tethering approach provides a novel and general strategy for discovering such cooperative binding interactions in specific, flexible regions of protein structure.
Organizational Affiliation: 
Sunesis Pharmaceuticals, 341 Oyster Point Boulevard, South San Francisco, California 94080, USA.