The crystal structure of human interferon beta at 2.2-A resolution.
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Karpusas M, Nolte M, Benton CB, Meier W, Lipscomb WN, Goelz S
The crystal structure of human interferon beta at 2.2-A resolution.
Proc Natl Acad Sci U S A. 1997 Oct 28;94(22):11813-8.
- PubMed ID
- 9342320 [ View in PubMed]
- Abstract
Type I interferons (IFNs) are helical cytokines that have diverse biological activities despite the fact that they appear to interact with the same receptor system. To achieve a better understanding of the structural basis for the different activities of alpha and beta IFNs, we have determined the crystal structure of glycosylated human IFN-beta at 2.2-A resolution by molecular replacement. The molecule adopts a fold similar to that of the previously determined structures of murine IFN-beta and human IFN-alpha2b but displays several distinct structural features. Like human IFN-alpha2b, human IFN-beta contains a zinc-binding site at the interface of the two molecules in the asymmetric unit, raising the question of functional relevance for IFN-beta dimers. However, unlike the human IFN-alpha2b dimer, in which homologous surfaces form the interface, human IFN-beta dimerizes with contact surfaces from opposite sides of the molecule. The relevance of the structure to the effects of point mutations in IFN-beta at specific exposed residues is discussed. A potential role of ligand-ligand interactions in the conformational assembly of IFN receptor components is discussed.