Structural Basis for Interaction of FGF-1, FGF-2, and FGF-7 with Different Heparan Sulfate Motifs
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- 作者：Sheng Ye ; Yongde Luo ; Weiqin Lu ; Richard B. Jones ; Robert J. Linhardt ; Ishan Capila ; Toshihiko Toida ; Mikio Kan ; Huguette Pelletier ; and Wallace L. McKeehan
- 刊名：Biochemistry
- 出版年：2001
- 出版时间：December 4, 2001
- 年：2001
- 卷：40
- 期：48
- 页码：14429 - 14439
- 全文大小：582K
- 年卷期：v.40,no.48(December 4, 2001)
- ISSN：1520-4995
文摘
Stromal cell-derived FGF-7 binds and activates only the resident FGFR2IIIb in epithelial cellswhile FGF-1 and FGF-2 exhibit a broader interaction with multiple isoforms of FGFR. Here we reportthe structure of FGF-7 that has been solved to 3.1 Å resolution by molecular replacement with the structureof a dual function chimera of FGF-7 and FGF-1 (FGF-7/1) which was resolved to 2.3 Å. Comparison ofthe FGF-7 structure to that of FGF-1 and FGF-2 revealed the strongly conserved C
backbone among thethree FGF polypeptides and the surface hydrophobic patch that forms the primary receptor-binding domain.In contrast, a decrease and dispersion of the positive surface charge density characterized the heparin-binding domain of FGF-7 defined by homology to that of FGF-1 and FGF-2 in complexes with heparin.A simple heparin hexasaccharide that cocrystallized with FGF-1 and FGF-2 and protected both againstprotease in solution failed to exhibit the same properties with FGF-7. In contrast to FGF-1 and FGF-2,protection of FGF-7 was enhanced by heparin oligosaccharides of increased length with those exhibitinga 3-O-sulfate being the most effective. Protection of FGF-7 required interaction with specifically thefraction of crude heparin retained on antithrombin affinity columns. Conversely, heparin enriched byaffinity for immobilized FGF-7 exhibited anti-factor Xa activity similar to that purified on an antithrombinaffinity matrix. In contrast, an FGF-1 affinity matrix enriched the fraction of crude heparin with lowanti-factor Xa activity. The results provide a structural basis to suggest that the unique FGF-7 heparin-binding (HB) domain underlies a specific restriction in respect to composition and length of the heparansulfate motif that may impact specificity of localization, stability, and trafficking of FGF-7 in themicroenvironment, and formation and activation of the FGFR2IIIb kinase signaling complex in epithelialcells.
backbone among thethree FGF polypeptides and the surface hydrophobic patch that forms the primary receptor-binding domain.In contrast, a decrease and dispersion of the positive surface charge density characterized the heparin-binding domain of FGF-7 defined by homology to that of FGF-1 and FGF-2 in complexes with heparin.A simple heparin hexasaccharide that cocrystallized with FGF-1 and FGF-2 and protected both againstprotease in solution failed to exhibit the same properties with FGF-7. In contrast to FGF-1 and FGF-2,protection of FGF-7 was enhanced by heparin oligosaccharides of increased length with those exhibitinga 3-O-sulfate being the most effective. Protection of FGF-7 required interaction with specifically thefraction of crude heparin retained on antithrombin affinity columns. Conversely, heparin enriched byaffinity for immobilized FGF-7 exhibited anti-factor Xa activity similar to that purified on an antithrombinaffinity matrix. In contrast, an FGF-1 affinity matrix enriched the fraction of crude heparin with lowanti-factor Xa activity. The results provide a structural basis to suggest that the unique FGF-7 heparin-binding (HB) domain underlies a specific restriction in respect to composition and length of the heparansulfate motif that may impact specificity of localization, stability, and trafficking of FGF-7 in themicroenvironment, and formation and activation of the FGFR2IIIb kinase signaling complex in epithelialcells.