Defining the Interleukin-8-binding Domain of Heparan Sulfate

• Published in: Journal of chemical biology 1998-06, Vol.273 (25), p.15487-15493
• Main Authors: Spillmann, D, Witt, D, Lindahl, U
• Format: Article
• Language: English
• Subjects: Binding Sites; Dimerization; Escherichia coli; Heparin - metabolism; Heparitin Sulfate - metabolism; Humans; Interleukin-8 - metabolism; MEDICIN; MEDICINE; Oligosaccharides - metabolism; Structure-Activity Relationship
• ISSN: 0021-9258; 1864-6158; 1864-6166; 1083-351X
• DOI: 10.1074/jbc.273.25.15487

Interleukin-8, a member of the C X C chemokine family, has been shown to bind to glycosaminoglycans. It has been suggested that heparan sulfate on cell surfaces could provide specific ligand sites on endothelial cells to retain the highly diffusible inflammatory chemokine for presentation to leukocytes. By using selectively modified heparin and heparan sulfate fragments in a nitrocellulose filter trapping system, we have analyzed sequence requirements for interleukin-8 binding to heparin/heparan sulfate. We demonstrate that the affinity of a monomeric interleukin-8 molecule for heparin/heparan sulfate is too weak to allow binding at physiological ionic strength, whereas the dimeric form of the protein mediates binding to two sulfated domains of heparan sulfate. These domains, each an N -sulfated block of ∼6 monosaccharide units, are contained within an ∼22–24-mer sequence and are separated by a region of ≤14 monosaccharide residues that may be fully N -acetylated. Binding to interleukin-8 correlates with the occurrence of the di- O -sulfated disaccharide unit -IdceA(2-OSO 3 )-GlcNSO 3 (6-OSO 3 )-. We suggest that the heparan sulfate sequence binds in horseshoe fashion over two antiparallel-oriented helical regions on the dimeric protein.