CCR2 chemokines bind selectively to acetylated heparan sulfate octasaccharides.
Chemokines participate in well documented interactions with glycosaminoglycans (GAGs). Although many chemokine amino acid residues involved in binding have been identified, much less is known about the bound regions of GAG. Heparan sulfate (HS) is the predominant cell surface GAG, and its heterogeneous nature offers proteins a variety of structural motifs with which to interact. In the present study, we describe the interactions of three CC chemokines, MCP-1/CCL2, MCP-2/CCL8, and MCP-3/CCL7, with HS-derived oligosaccharides. To this end, we generated and characterized a complex HS octasaccharide library containing 17 different octasaccharide compositions based on acetyl and sulfate group content. Electrospray ionization mass spectrometry was used to detect chemokine-HS octasaccharide complexes in the bound state, and an affinity purification protocol was used to select and identify chemokine-binding octasaccharides from the complex mixture. The results indicate that HS octasaccharide sulfation is the foremost requirement for chemokine binding. However, within octasaccharides of constant charge density, acetylation is also observed to augment binding, suggesting that there may be as yet undiscovered specificity in the chemokine-HS interaction.
Schenauer
Matthew R
MR
Genome Center, Department of Chemistry, University of California, Davis, California 95616, USA.
Yu
Yonghao
Y
Sweeney
Matthew D
MD
Leary
Julie A
JA
D000107:Acetylation; D000595:Amino Acid Sequence; D000818:Animals; D019742:Chemokines, CC / Q000737:chemistry* / Q000378:metabolism; D006497:Heparan Sulfate / Q000737:chemistry* / Q000378:metabolism; D006801:Humans; D009844:Oligosaccharides / Q000737:chemistry* / Q000378:metabolism; D011485:Protein Binding; D054390:Receptors, CCR2; D019707:Receptors, Chemokine; D021241:Spectrometry, Mass, Electrospray Ionization; D013552:Swine
D019742:Chemokines, CC; D006497:Heparan Sulfate; D009844:Oligosaccharides; D054390:Receptors, CCR2; D019707:Receptors, Chemokine; C515334:CCR2 protein, human