|1m47, resolution 1.99Å ()|
|Related:||1m48, 1m49, 1m4a, 1m4b, 1m4c|
Crystal Structure of Human Interleukin-2
Understanding binding properties at protein-protein interfaces has been limited to structural and mutational analyses of natural binding partners or small peptides identified by phage display. Here, we present a high-resolution analysis of a nonpeptidyl small molecule, previously discovered by medicinal chemistry [Tilley, J. W., et al. (1997) J. Am. Chem. Soc. 119, 7589-7590], which binds to the cytokine IL-2. The small molecule binds to the same site that binds the IL-2 alpha receptor and buries into a groove not seen in the free structure of IL-2. Comparison of the bound and several free structures shows this site to be composed of two subsites: one is rigid, and the other is highly adaptive. Thermodynamic data suggest the energy barriers between these conformations are low. The subsites were dissected by using a site-directed screening method called tethering, in which small fragments were captured by disulfide interchange with cysteines introduced into IL-2 around these subsites. X-ray structures with the tethered fragments show that the subsite-binding interactions are similar to those observed with the original small molecule. Moreover, the adaptive subsite tethered many more compounds than did the rigid one. Thus, the adaptive nature of a protein-protein interface provides sites for small molecules to bind and underscores the challenge of applying structure-based design strategies that cannot accurately predict a dynamic protein surface.
Binding of small molecules to an adaptive protein-protein interface., Arkin MR, Randal M, DeLano WL, Hyde J, Luong TN, Oslob JD, Raphael DR, Taylor L, Wang J, McDowell RS, Wells JA, Braisted AC, Proc Natl Acad Sci U S A. 2003 Feb 18;100(4):1603-8. Epub 2003 Feb 11. PMID:12582206
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
[IL2_HUMAN] Note=A chromosomal aberration involving IL2 is found in a form of T-cell acute lymphoblastic leukemia (T-ALL). Translocation t(4;16)(q26;p13) with involves TNFRSF17.
[IL2_HUMAN] Produced by T-cells in response to antigenic or mitogenic stimulation, this protein is required for T-cell proliferation and other activities crucial to regulation of the immune response. Can stimulate B-cells, monocytes, lymphokine-activated killer cells, natural killer cells, and glioma cells.
About this Structure
- Arkin MR, Randal M, DeLano WL, Hyde J, Luong TN, Oslob JD, Raphael DR, Taylor L, Wang J, McDowell RS, Wells JA, Braisted AC. Binding of small molecules to an adaptive protein-protein interface. Proc Natl Acad Sci U S A. 2003 Feb 18;100(4):1603-8. Epub 2003 Feb 11. PMID:12582206 doi:http://dx.doi.org/10.1073/pnas.252756299
- Hyde J, Braisted AC, Randal M, Arkin MR. Discovery and characterization of cooperative ligand binding in the adaptive region of interleukin-2. Biochemistry. 2003 Jun 3;42(21):6475-83. PMID:12767230 doi:10.1021/bi034138g