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THE CRYSTAL STRUCTURE OF FIBROBLAST GROWTH FACTOR 7/1 CHIMERATHE CRYSTAL STRUCTURE OF FIBROBLAST GROWTH FACTOR 7/1 CHIMERA
Structural highlights
FunctionFGF7_RAT Growth factor active on keratinocytes. Possible major paracrine effector of normal epithelial cell proliferation. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedStromal cell-derived FGF-7 binds and activates only the resident FGFR2IIIb in epithelial cells while FGF-1 and FGF-2 exhibit a broader interaction with multiple isoforms of FGFR. Here we report the structure of FGF-7 that has been solved to 3.1 A resolution by molecular replacement with the structure of a dual function chimera of FGF-7 and FGF-1 (FGF-7/1) which was resolved to 2.3 A. Comparison of the FGF-7 structure to that of FGF-1 and FGF-2 revealed the strongly conserved Calpha backbone among the three 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 against protease 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 exhibiting a 3-O-sulfate being the most effective. Protection of FGF-7 required interaction with specifically the fraction of crude heparin retained on antithrombin affinity columns. Conversely, heparin enriched by affinity for immobilized FGF-7 exhibited anti-factor Xa activity similar to that purified on an antithrombin affinity matrix. In contrast, an FGF-1 affinity matrix enriched the fraction of crude heparin with low anti-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 heparan sulfate motif that may impact specificity of localization, stability, and trafficking of FGF-7 in the microenvironment, and formation and activation of the FGFR2IIIb kinase signaling complex in epithelial cells. Structural basis for interaction of FGF-1, FGF-2, and FGF-7 with different heparan sulfate motifs.,Ye S, Luo Y, Lu W, Jones RB, Linhardt RJ, Capila I, Toida T, Kan M, Pelletier H, McKeehan WL Biochemistry. 2001 Dec 4;40(48):14429-39. PMID:11724555[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences |
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