Crystal Structures of Oligomeric Forms of the Ip-10/Cxcl10 ChemokineSwaminathan, G.J., Holloway, D.E., Colvin, R.A., Campanella, G.K., Papageorgiou, A.C., Luster, A.D., Acharya, K.R.
(2003) Structure 11: 521
- PubMed: 12737818
- DOI: https://doi.org/10.1016/s0969-2126(03)00070-4
- Primary Citation of Related Structures:
1O7Y, 1O7Z, 1O80
- PubMed Abstract:
We have determined the structure of wild-type IP-10 from three crystal forms. The crystals provide eight separate models of the IP-10 chain, all differing substantially from a monomeric IP-10 variant examined previously by NMR spectroscopy. In each crystal form, IP-10 chains form conventional beta sheet dimers, which, in turn, form a distinct tetrameric assembly. The M form tetramer is reminiscent of platelet factor 4, whereas the T and H forms feature a novel twelve-stranded beta sheet. Analytical ultracentrifugation indicates that, in free solution, IP-10 exists in a monomer-dimer equilibrium with a dissociation constant of 9 microM. We propose that the tetrameric structures may represent species promoted by the binding of glycosaminoglycans. The binding sites for several IP-10-neutralizing mAbs have also been mapped.
Department of Biology and Biochemistry, University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom.