Ingham K C, Brew S A, Atha D H
Biochemistry Laboratory, American Red Cross Biomedical Research and Development, Rockville, MD 20855.
Biochem J. 1990 Dec 15;272(3):605-11. doi: 10.1042/bj2720605.
Fluorescence polarization, gel exclusion chromatography and affinity chromatography were used to characterize the interaction of heparins of different size with human plasma fibronectin (Fn) and several of its isolated domains. The fluid-phase interaction of Fn with heparin was dominated by the 30 kDa and 40 kDa Hep-2 domains located near the C-terminal ends of the A and B chains respectively. The 30 kDa Hep-2A domain from the heavy chain was indistinguishable from the 40 kDa Hep-2B domain in this respect; the presence of an additional type III homology unit in the latter had no effect on the binding. Evidence was provided that each Hep-2 domain has two binding sites for heparin. The N-terminal Hep-1 domain reacted weakly in fluid phase even though it binds strongly to immobilized heparin. Fn and Hep-2 fragments were rather undiscriminating in their reaction with fluoresceinamine-labelled heparins of different sizes. However, oligosaccharides smaller than the tetradecasaccharide (14-mer) bound Fn with a 5-10-fold lower affinity. These results suggest that the Hep-2 domains of Fn are able to recognize a broad spectrum of oligosaccharides that presumably vary significantly with respect to the amount and spatial distribution of charge.
利用荧光偏振、凝胶排阻色谱和亲和色谱对不同大小的肝素与人血浆纤连蛋白（Fn）及其几个分离结构域之间的相互作用进行了表征。Fn与肝素的液相相互作用主要由分别位于A链和B链C末端附近的30 kDa和40 kDa Hep-2结构域主导。在这方面，重链的30 kDa Hep-2A结构域与40 kDa Hep-2B结构域没有区别；后者中额外的III型同源单位对结合没有影响。有证据表明每个Hep-2结构域有两个肝素结合位点。N末端的Hep-1结构域在液相中反应较弱，尽管它与固定化肝素强烈结合。Fn和Hep-2片段与不同大小的荧光胺标记肝素反应时没有明显的选择性。然而，小于十四糖（14聚体）的寡糖与Fn的结合亲和力低5-10倍。这些结果表明，Fn的Hep-2结构域能够识别广泛的寡糖，这些寡糖的电荷数量和空间分布可能有很大差异。
