Ehnis T, Dieterich W, Bauer M, Kresse H, Schuppan D
Free University of Berlin, Klinikum Benjamin Franklin, Department of Gastroenterology, Hindenburgdamm 30, D-12200 Berlin, Germany.
J Biol Chem. 1997 Aug 15;272(33):20414-9. doi: 10.1074/jbc.272.33.20414.
Through its ability to bind extracellular matrix constituents and growth factors the small leucine-rich chondroitin/dermatan sulfate proteoglycan decorin which is present in many types of connective tissues may play an important biological role in remodeling and maintenance of extracellular matrices during inflammation, fibrosis, and cancer growth. In this study we investigated the known binding of decorin to human collagen XIV. This binding was unaffected when the small collagenous moiety of collagen XIV was removed with collagenase. Therefore, fragments covering the large noncollagenous domain NC3 of collagen XIV were expressed in Escherichia coli, each fused to a 26-kDa fragment of glutathione S-transferase. Using radioiodinated decorin as ligand for the immobilized fusion proteins, a binding site that interacted with the decorin core protein could be assigned to the NH2-terminal fibronectin type III repeat of collagen XIV. In addition, an auxiliary binding site located COOH-terminal to this fibronectin type III repeat interacted with the glycosaminoglycan component of decorin.
富含亮氨酸的小分子软骨素/硫酸皮肤素蛋白聚糖核心蛋白聚糖存在于多种结缔组织中，它能够结合细胞外基质成分和生长因子，在炎症、纤维化和癌症生长过程中，细胞外基质的重塑和维持方面可能发挥重要的生物学作用。在本研究中，我们研究了核心蛋白聚糖与人类胶原蛋白XIV已知的结合情况。用胶原酶去除胶原蛋白XIV的小胶原部分后，这种结合不受影响。因此，覆盖胶原蛋白XIV大的非胶原结构域NC3的片段在大肠杆菌中表达，每个片段都与谷胱甘肽S-转移酶的26 kDa片段融合。使用放射性碘化核心蛋白聚糖作为固定化融合蛋白的配体，可以将与核心蛋白聚糖核心蛋白相互作用的结合位点定位到胶原蛋白XIV的NH2末端纤连蛋白III型重复序列。此外，位于该纤连蛋白III型重复序列COOH末端的一个辅助结合位点与核心蛋白聚糖的糖胺聚糖成分相互作用。
