NMR solution structure and receptor peptide binding of the CC chemokine eotaxin-2.
The human CC chemokine eotaxin-2 is a specific agonist for the chemokine receptor CCR3 and may play a role in the recruitment of eosinophils in allergic diseases and parasitic infections. We report the solution structure of eotaxin-2 determined using heteronuclear and triple resonance NMR methods. A family of 20 structures was calculated by hybrid distance geometry-simulated annealing from 854 NOE distance restraints, 48 dihedral angle restraints, and 12 hydrogen bond restraints. The structure of eotaxin-2 (73 amino acid residues) consists of a helical turn (residues 17-20) followed by a 3-stranded antiparallel beta-sheet (residues 22-26, 37-41, and 44-49) and an alpha-helix (residues 54-66). The N-loop (residues 9-16) is packed against both the sheet and the helix with the two conserved disulfide bonds tethering the N-terminal/N-loop region to the beta-sheet. The average backbone and heavy atom rmsd values of the 20 structures (residues 7-66) are 0.52 and 1.13 A, respectively. A linear peptide corresponding to the N-terminal region of CCR3 binds to eotaxin-2, inducing concentration-dependent chemical shift changes or line broadening of many residues. The distribution of these residues suggests that the peptide binds into an extended groove located at the interface between the N-loop and the beta2-beta3 hairpin. The receptor peptide may also interact with the N-terminus of the chemokine and part of the alpha-helix. Comparison of the eotaxin-2 structure with those of related chemokines indicates several structural features that may contribute to receptor specificity.
Department of Chemistry, Indiana University, Bloomington 47405-0001, USA.
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Mayer
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D000595:Amino Acid Sequence; D001483:Base Sequence; D001665:Binding Sites; D054423:Chemokine CCL24; D019742:Chemokines, CC / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D017931:DNA Primers / Q000235:genetics; D006801:Humans; D066298:In Vitro Techniques; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011485:Protein Binding; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D054397:Receptors, CCR3; D019707:Receptors, Chemokine / Q000737:chemistry* / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D055672:Static Electricity; D013816:Thermodynamics
C515484:CCL24 protein, human; C515350:CCR3 protein, human; D054423:Chemokine CCL24; D019742:Chemokines, CC; D017931:DNA Primers; D054397:Receptors, CCR3; D019707:Receptors, Chemokine; D011993:Recombinant Fusion Proteins