Wiberg C, Hedbom E, Khairullina A, Lamandé S R, Oldberg A, Timpl R, Mörgelin M, Heinegård D
Department of Cell and Molecular Biology, University of Lund, BMC Plan C12, Lund S-221 84, Sweden.
J Biol Chem. 2001 Jun 1;276(22):18947-52. doi: 10.1074/jbc.M100625200. Epub 2001 Mar 19.
The binding of native biglycan and decorin to pepsin-extracted collagen VI from human placenta was examined by solid phase assay and by measurement of surface plasmon resonance in the BIAcore(TM)2000 system. Both proteoglycans exhibited a strong affinity for collagen VI with dissociation constants (K(D)) of approximately 30 nm. Removal of the glycosaminoglycan chains by chondroitinase ABC digestion did not significantly affect binding. In coprecipitation experiments, biglycan and decorin bound to collagen VI and equally competed with the other, suggesting that biglycan and decorin bind to the same binding site on collagen VI. This was confirmed by electron microscopy after negative staining of complexes between gold-labeled proteoglycans and collagen VI, demonstrating that both biglycan and decorin bound exclusively to a domain close to the interface between the N terminus of the triple helical region and the following globular domain. In solid phase assay using recombinant collagen VI fragments, it was shown that the alpha2(VI) chain probably plays a role in the interaction.
通过固相分析以及在BIAcore(TM)2000系统中测量表面等离子体共振，研究了天然双糖链蛋白聚糖和核心蛋白聚糖与人胎盘胃蛋白酶提取的胶原蛋白VI的结合情况。两种蛋白聚糖对胶原蛋白VI均表现出很强的亲和力，解离常数（K(D)）约为30 nM。用软骨素酶ABC消化去除糖胺聚糖链对结合没有显著影响。在共沉淀实验中，双糖链蛋白聚糖和核心蛋白聚糖与胶原蛋白VI结合，并相互间存在同等程度的竞争，这表明双糖链蛋白聚糖和核心蛋白聚糖结合到胶原蛋白VI上的同一个结合位点。在用金标记的蛋白聚糖与胶原蛋白VI形成复合物进行负染后，通过电子显微镜证实了这一点，结果表明双糖链蛋白聚糖和核心蛋白聚糖都仅结合到靠近三螺旋区域N端与后续球状结构域之间界面的一个结构域上。在使用重组胶原蛋白VI片段的固相分析中，结果表明α2(VI)链可能在这种相互作用中发挥作用。
