Cartilage oligomeric matrix protein shows high affinity zinc-dependent interaction with triple helical collagen
Cartilage oligomeric matrix protein shows high affinity zinc-dependent interaction with triple helical collagen
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DOI：
10.1074/jbc.273.32.20397
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发表时间：
1998-08-07
影响因子：
4.8
通讯作者：
Heinegård, D
中科院分区：
文献类型：
--
作者：
Rosenberg, K;Olsson, H;Heinegård, D
软骨和肌腱细胞外基质由胶原、蛋白多糖和许多非胶原蛋白组成。胶原寡聚基质蛋白（COMP）是一种重要的此类蛋白质，在结构上与血小板反应蛋白相关。我们发现，天然COMP与胶原蛋白I/II和前胶原蛋白I/II结合，并且这种相互作用依赖于二价阳离子Zn 2+或Ni 2+，而Ca 2+、Mg 2+和Mn 2+不促进结合。使用固相测定，Scatchard分析确定了一类结合位点，在Zn 2+存在下解离常数（Kd）接近1.5 nM。利用表面等离子体共振的研究证实了这一结果。此外，金属螯合层析证明COMP结合Zn 2+和Ni 2+。电子显微镜显示，相互作用发生在四个定义的网站上的300 nm的胶原和前胶原分子。两个位于靠近每一端，两个在126和206 nm，分别从C-末端，COMP相互作用通过其C-末端球状域和显着只有在存在的Zn 2+。
Cartilage and tendon extracellular matrices are composed of collagens, proteoglycans, and a number of noncollagenous proteins. Cartilage oligomeric matrix protein (COMP) is a prominent such protein, structurally related to the thrombospondins. We found that native COMP binds to collagen I/II and procollagen I/II and that the interaction is dependent on the divalent cations Zn2+ or Ni2+, whereas Ca2+, Mg2+, and Mn2+ did not promote binding. Using a solid phase assay, Scatchard analysis identified one class of binding site with a dissociation constant (K-d) close to 1.5 nM in the presence of Zn2+. The results were confirmed by studies using surface plasmon resonance. Furthermore, metal chelate chromatography demonstrated that COMP bound Zn2+ and Ni2+. Electron microscopy showed that the interaction occurred at four defined sites on the 300-nm collagen and procollagen molecules. Two were located close to each end, and two at 126 and 206 nm, respectively, from the C-terminal, COMP interacted via its C-terminal globular domain and significantly only in the presence of Zn2+.