NATURE OF THE INTERACTION OF HEPARIN WITH ACIDIC FIBROBLAST GROWTH-FACTOR
NATURE OF THE INTERACTION OF HEPARIN WITH ACIDIC FIBROBLAST GROWTH-FACTOR
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DOI：
10.1021/bi00071a026
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发表时间：
1993-05-25
期刊：
影响因子：
2.9
通讯作者：
MATTSSON, L
中科院分区：
文献类型：
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作者：
MACH, H;VOLKIN, DB;MATTSSON, L
人酸性成纤维细胞生长因子（aFGF）与肝素的结合已通过各种不同的方法进行了分析，以更好地阐明这种蛋白质/硫酸多糖相互作用的性质。静态和动态光散射以及分析超离心分析表明，14-15个aFGF分子可以结合到16-kDa肝素链，其中约10个相对均匀地结合到高亲和力位点。基于表面等离子体共振实验，这些后一位点的解离常数估计为约50-140 nM，在所述表面等离子体共振实验中测量aFGF与固定化肝素相互作用的缔合和解离速率。肝素上aFGF结合位点的大小也通过aFGF/肝素复合物的肝素裂解酶消化，然后分离和表征受保护的寡糖来确定。最小的aFGF保护的寡糖与DELTAUA 2S（1->4）-a-D-GlcNp 2S 6S（1->4）-a-L-IdoAp-2S（1->4）-a-D-GlcNp 2S 6S（其中DELTAUA代表4-脱氧-a-L-苏型-己-4-烯吡喃糖醛酸，S是硫酸盐）共迁移。因此，FGF似乎以高密度（每4-5个多糖单元一个分子）和高亲和力与肝素结合。这潜在地提供了生长因子的浓缩的、稳定的储存形式，其可以响应于适当的刺激而被释放用于受体介导的细胞活化。如Ornitz等人所建议的，也可能是乙酰肝素链的高度硫酸化区域上的aFGF分子的紧密接近可能参与受体聚集的诱导。
The binding of human acidic fibroblast growth factor (aFGF) to heparin has been analyzed by a variety of different approaches to better elucidate the nature of this protein/sulfated polysaccharide interaction. Static and dynamic light scattering as well as analytical ultracentrifugation analyses indicates that 14-15 molecules of aFGF can bind to a 16-kDa heparin chain, with approximately 10 of these bound relatively uniformly to high-affinity sites. The dissociation constants of these latter sites are estimated to be approximately 50-140 nM on the basis of surface plasmon resonance experiments in which the association and dissociation rates of aFGF interaction with immobilized heparin were measured. The size of the binding site of aFGF on heparin was also determined by heparin lyase digestion of aFGF/heparin complexes followed by isolation and characterization of protected oligosaccharides. The smallest aFGF-protected oligosaccharide comigrated with DELTAUA2S(1-->4)-alpha-D-GlcNp2S6S(1-->4)-alpha-L-IdoAp-2S(1-->4)-alpha-D-GlcNp2S6S (where DELTAUA represents 4-deoxy-alpha-L-threo-hex-4-enopyranosyluronic acid and S is sulfate). Thus, a FGF appears to bind at high density (one molecule every 4-5 polysaccharide units) and with high affinity to heparin. This potentially provides a concentrated, stabilized storage form of the growth factor that can be released for receptor-mediated cellular activation in response to the proper stimuli. It is also possible that close proximity of aFGF molecules on the highly sulfated regions of heparan chains may be involved in the induction of receptor aggregation as suggested by Ornitz et al.