Mollenhauer J, von der Mark K
Max-Planck-Institut für Biochemie, Abt. Bindegewebsforschung, Martinsried, FRG.
EMBO J. 1983;2(1):45-50. doi: 10.1002/j.1460-2075.1983.tb01378.x.
A collagen-binding glycoprotein was isolated from purified chick chondrocyte surface membranes by affinity chromatography on type II collagen-Sepharose. The purified glycoprotein has an apparent mol. wt. of 31,000 and binds to native chick collagen types I, II, III, V and M. Although it contains 30% carbohydrates, the majority of which is fucose, it is hydrophobic and soluble only in detergents. The integral membrane protein character of the 31-K protein became apparent from its ability to insert into lecithin vesicles. Liposome-inserted 31-K protein binds 125I-labelled type II collagen in the presence of 0.5 M NaCl, while detergent-solubilized 31-K protein is dissociated from type II collagen by 0.05-0.1 M NaCl. Electron microscopic studies employing the rotary shadowing technique indicate that 31-K protein particles bind to the ends of collagen molecules. We propose that this glycoprotein serves as anchorage site for extracellular collagen to the chondrocyte membrane and thus may be involved in cell-matrix interactions in cartilage.
通过在II型胶原-琼脂糖凝胶上进行亲和层析，从纯化的鸡软骨细胞表面膜中分离出一种胶原结合糖蛋白。纯化后的糖蛋白表观分子量为31,000，可与天然鸡I型、II型、III型、V型和M型胶原结合。尽管它含有30%的碳水化合物，其中大部分是岩藻糖，但它具有疏水性，仅溶于去污剂。31-K蛋白的整合膜蛋白特性从其插入卵磷脂囊泡的能力中得以显现。在0.5 M NaCl存在的情况下，插入脂质体的31-K蛋白可结合125I标记的II型胶原，而用去污剂溶解的31-K蛋白在0.05 - 0.1 M NaCl作用下会与II型胶原解离。采用旋转阴影技术的电子显微镜研究表明，31-K蛋白颗粒与胶原分子的末端结合。我们推测这种糖蛋白作为细胞外胶原与软骨细胞膜的锚定位点，因此可能参与软骨中的细胞-基质相互作用。
