Mapping the binding surface of interleukin-8 complexed with an N-terminal fragment of the type 1 human interleukin-8 receptor.
Interleukin-8 and its receptors are key mediators of immune and inflammatory responses. Heteronuclear NMR spectroscopy has been utilized to map the binding surface on interleukin-8 (IL-8) for an N-terminal fragment of the human Type-1 IL-8 receptor. A peptide corresponding to residues 1-40 of the IL-8 type 1 receptor (IL8-r1) was titrated into a sample of uniformly 15N-labeled IL-8. IL8-r1 binds to IL-8 with a dissociation constant of 170 +/- 50 microM assuming the peptide binds with a stoichiometry of one peptide per IL-8 monomer, exchanges rapidly (> 900 s-1) between free and bound states, and selectively perturbs the chemical environment of several IL-8 residues. The binding surface on IL-8 suggested by our results is comprised of residues in strand beta 3 of the beta-sheet (Glu48 to Cys50), the turn preceding beta 3 (Ser44), the C-terminal alpha-helix (Val61) and the irregular N-terminal loop region (Thr12, Lys15, Phe17, His18, Lys20 and Phe21). The IL-8 dimer appears to present two symmetrical binding surfaces for the IL8-r1 peptide, suggesting two receptor peptides may bind per dimer.
Clubb
R T
RT
Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892.
Omichinski
J G
JG
Clore
G M
GM
Gronenborn
A M
AM
D000595:Amino Acid Sequence; D001665:Binding Sites; D006801:Humans; D016209:Interleukin-8 / Q000737:chemistry / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008969:Molecular Sequence Data; D018123:Receptors, Interleukin / Q000737:chemistry / Q000378:metabolism*; D023062:Receptors, Interleukin-8A; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism
D016209:Interleukin-8; D018123:Receptors, Interleukin; D023062:Receptors, Interleukin-8A; D011994:Recombinant Proteins