Coacervation characteristics of recombinant human tropoelastin
Coacervation characteristics of recombinant human tropoelastin
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DOI：
10.1111/j.1432-1033.1997.00092.x
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发表时间：
1997-11-15
期刊：
影响因子：
--
通讯作者：
Weiss, AS
中科院分区：
文献类型：
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作者：
Vrhovski, B;Jensen, S;Weiss, AS
可溶性弹性蛋白原分子的凝聚的特征在于在适当并置的离子条件、蛋白质浓度和pH下随着温度的升高而发生可逆的缔合。凝聚在这些弹性蛋白前体在弹性纤维形成中的组装中起关键作用。为了检查生理参数对原弹性蛋白分子缔合能力的影响，通过在宽的温度范围内的光散射以荧光光度法监测重组人原弹性蛋白的溶液。重组人弹性蛋白原的凝聚受到蛋白质和NaCl浓度的强烈影响，并且在较小程度上受pH值的影响。当这些参数中的每一个变化时，朝向最大关联的趋势是明显的。值得注意的是，在37 ℃、150 mM NaCl和pH 7-8下发现最佳凝聚。利用时间过程产生的数据，对热力学参数进行了估计。这些估计证实，凝聚是吸热的，是由一个强大的熵贡献的标志。重组人弹性蛋白原的圆二色性显示，其结构不是随机的，而是与全β蛋白的结构（二级结构估计为3% α-螺旋、41% β-折叠、21% β-转角和33%其他）相容，表现出如先前对于弹性蛋白原群体和来自天然来源的可溶性弹性蛋白所见的光谱。
Coacervation of soluble tropoelastin molecules is characterized by thermodynamically reversible association as temperature is increased under appropriately juxtaposed ionic conditions, protein concentration and pH. Coacervation plays a critical role in the assembly of these elastin precursors in elastic fiber formation. To examine the effect of physiological parameters on the ability of tropoelastin molecules to associate, solutions of recombinant human tropoelastin were monitored spectrophotometrically by light scattering over a broad, range of temperatures. Coacervation of recombinant human tropoelastin is strongly influenced by the concentration of protein and NaCl and to a lesser extent on pH. Trends towards maximal association are apparent when each of these parameters is varied. Remarkably, optimal coacervation is found at 37 degrees C, 150 mM NaCl and pH 7-8. Using the data generated by time courses, estimates of thermodynamic parameters wen made. These estimates confirm that coacervation is endothermic and is marked by a strong entropic contribution. Circular dichroism of recombinant human tropoelastin revealed that, rather than being random, the structure is compatible with being largely that, of an all-beta protein (with secondary structure estimated to be 3% alpha-helix, 41% beta-sheet, 21% beta-turn and 33% other), exhibiting a spectrum as previously seen for tropoelastin populations and soluble elastin from naturally-derived sources.