Author:

Keywords:

Science & Technology, Life Sciences & Biomedicine, Physical Sciences, Biochemistry & Molecular Biology, Chemistry, Multidisciplinary, Chemistry, heparan sulfate, heparin, hyaluronic acid, glycosaminoglycan, peptides, glycosaminoglycan-binding motif, chemokine, CHEMOKINE, HEPARIN, IDENTIFICATION, EXTRAVASATION, SITES, Animals, Binding Sites, CHO Cells, Cricetulus, Heparin, Low-Molecular-Weight, Heparitin Sulfate, Peptides, Protein Binding, 11A4220N|11A4222N#55341643, C16/17/010#54271312, 0399 Other Chemical Sciences, 0604 Genetics, 0699 Other Biological Sciences, Chemical Physics, 3101 Biochemistry and cell biology, 3107 Microbiology, 3404 Medicinal and biomolecular chemistry

Abstract:

Although glycosaminoglycan (GAG)-protein interactions are important in many physiological and pathological processes, the structural requirements for binding are poorly defined. Starting with GAG-binding peptide CXCL9(74-103), peptides were designed to elucidate the contribution to the GAG-binding affinity of different: (1) GAG-binding motifs (i.e., BBXB and BBBXXB); (2) amino acids in GAG-binding motifs and linker sequences; and (3) numbers of GAG-binding motifs. The affinity of eight chemically synthesized peptides for various GAGs was determined by isothermal fluorescence titration (IFT). Moreover, the binding of peptides to cellular GAGs on Chinese hamster ovary (CHO) cells was assessed using flow cytometry with and without soluble GAGs. The repetition of GAG-binding motifs in the peptides contributed to a higher affinity for heparan sulfate (HS) in the IFT measurements. Furthermore, the presence of Gln residues in both GAG-binding motifs and linker sequences increased the affinity of trimer peptides for low-molecular-weight heparin (LMWH), partially desulfated (ds)LMWH and HS, but not for hyaluronic acid. In addition, the peptides bound to cellular GAGs with differential affinity, and the addition of soluble HS or heparin reduced the binding of CXCL9(74-103) to cellular GAGs. These results indicate that the affinity and specificity of peptides for GAGs can be tuned by adapting their amino acid sequence and their number of GAG-binding motifs.