The molecular elasticity of the extracellular matrix protein tenascin
The molecular elasticity of the extracellular matrix protein tenascin
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DOI：
10.1038/30270
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发表时间：
1998-05-14
期刊：
影响因子：
64.8
通讯作者：
Fernandez, JM
中科院分区：
文献类型：
--
作者：
Oberhauser, AF;Marszalek, PE;Fernandez, JM
细胞外基质蛋白被认为提供了一个刚性的机械锚，支持和引导迁移和滚动细胞（1-4）。在这里，我们研究的机械性能的细胞外基质蛋白腱生蛋白通过使用原子力显微镜技术。我们的研究结果表明，肌腱蛋白是一种弹性蛋白。单个的腱生蛋白分子可以被拉伸到其静止长度的几倍。力-延伸曲线显示锯齿形图案，力的峰值在137 pN。这些峰相似，相距25 nm。通过对肌联蛋白的研究也得到了类似的结果（5）。我们也发现了类似的结果，通过研究重组腱蛋白片段，包括15纤连蛋白III型结构域的腱蛋白。这表明腱生蛋白图谱的可扩展性是由于其纤连蛋白III型结构域的拉伸诱导的解折叠。拉伸后，观察到的力减少到接近零时，腱生蛋白的重折叠，显示出双指数恢复与时间常数的42域重折叠每秒和0.5域每秒。前者的重折叠速度是任何先前报道的纤连蛋白III型结构域重折叠速度的两倍以上（6，7）。我们认为，模块化的纤连蛋白III型区域的可扩展性可能是重要的，在允许腱生蛋白配体键持续长时间的扩展。纤连蛋白III型模块的这些特性可广泛用于含有此类结构域的细胞外蛋白（8，9）。
Extracellular matrix proteins are thought to provide a rigid mechanical anchor that supports and guides migrating and rolling cells(1-4). Here we examine the mechanical properties of the extracellular matrix protein tenascin by using atomic-force-microscopy techniques. Our results indicate that tenascin is an elastic protein. Single molecules of tenascin could be stretched to several times their resting length. Force-extension curves showed a saw-tooth pattern, with peaks of force at 137 pN. These peaks were similar to 25 nm apart. Similar results have been obtained by study of titin(5). We also found similar results by studying recombinant tenascin fragments encompassing the 15 fibronectin type III domains of tenascin. This indicates that the extensibility of tenascin map be due to the stretch-induced unfolding of its fibronectin type III domains. Refolding of tenascin after stretching, observed when the force was reduced to near zero, showed a double-exponential recovery with time constants of 42 domains refolded per second and 0.5 domains per second. The former speed of refolding is more than twice as fast as any previously reported speed of refolding of a fibronectin type III domain(6,7). We suggest that the extensibility of the modular fibronectin type III region may be important in allowing tenascin-ligand bonds to persist over long extensions. These properties of fibronectin type III modules may be of widespread use in extracellular proteins containing such domain(8,9).