1md6

Publication Abstract from PubMed

Interleukin-1 (IL-1) F5 is a novel member of the IL-1 family. The IL-1 family are involved in innate immune responses to infection and injury. These cytokines bind to specific receptors and cause activation of NFkappaB and MAP kinase. IL-1F5 has a sequence identity of 44% to IL-1 receptor antagonist (IL-1Ra), a natural antagonist of the IL-1 system. Here we report the crystal structure of IL-1F5 to a resolution of 1.6 A. It has the same beta-trefoil fold as other IL-1 family members, and the hydrophobic core is well conserved. However, there are substantial differences in the loop conformations, structures that confer binding specificity for the cognate receptor to IL-1beta and the antagonist IL-1Ra. Docking and superimposition of the IL-1F5 structure suggest that is unlikely to bind to the interleukin1 receptor, consistent with biochemical studies. The structure IL-1F5 lacks features that confer antagonist properties on IL-1Ra, and we predict that like IL-1beta it will act as an agonist. These studies give insights into how distinct receptor specificities can evolve within related cytokine families.

High-resolution structure of murine interleukin 1 homologue IL-1F5 reveals unique loop conformations for receptor binding specificity.,Dunn EF, Gay NJ, Bristow AF, Gearing DP, O'Neill LA, Pei XY Biochemistry. 2003 Sep 23;42(37):10938-44. PMID:12974628^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.