Determination of reaction volumes and polymer distribution characteristics of tobacco mosaic virus coat protein.
Determination of reaction volumes and polymer distribution characteristics of tobacco mosaic virus coat protein.
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烟草花叶病毒外壳蛋白反应体积和聚合物分布特征的测定。
DOI：
10.1016/0003-2697(87)90653-1
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发表时间：
1987
影响因子：
2.9
通讯作者：
Schuster,TM
中科院分区：
文献类型：
--
作者：
Potschka,M;Schuster,TM
本文提出了一种在分析超离心装置中，由沉降速度实验定量测定反应体积的方法。结合用于检测压力诱导的解聚的第二种方法，可以探测聚合物分布的一般特征。我们表明，它是可能的，以确定如果一个样品是在亚基协会的平衡或亚稳态。我们的方法探测大分子聚集系统的小压力扰动并不限于使用离心机。该方法已被应用于烟草花叶病毒外壳蛋白（TMVP）的聚合的某些方面的特征。在无RNA的外壳蛋白棒中至少存在两种螺旋聚合物构象。较小的螺旋I聚合物被限制在低于约70个亚基（4至5个螺旋转角）的大小，并且在可以无限期地添加更多的亚基之前经历某种合作构象变化。与螺旋I相反，较大的螺旋II聚合物以更宽和偏斜的尺寸分布出现。在中等强度的聚合条件下，平衡状态可以包含两种类型的螺旋杆。对于两种类型的螺旋聚合物，添加三聚体的反应体积为-220 ml/mol。这些结果与以前的TMVP聚合的热力学分析的结果进行了比较。
A method that allows the quantitative determination of reaction volumes from sedimentation velocity experiments in an analytical ultracentrifuge is presented. Combined with a second method for detecting pressure-induced depolymerization, general characteristics of polymer distributions may be probed. We show that it is possible to determine if a sample is in an equilibrium or metastable state of subunit association. Our approach to probe macromolecular aggregation systems by small pressure perturbations is not restricted to the use of centrifuges. This method has been applied to characterize certain aspects of the polymerization of tobacco mosaic virus coat protein (TMVP). There are at least two helical polymer conformations in RNA-free coat protein rods. The smaller, helix I, polymers are limited to sizes below about 70 subunits (four to five helical turns) and undergo some kind of cooperative conformational change before further subunits may be added indefinitely. In contrast to helix I, the larger helix II polymers occur as broader and skewed size distributions. Under moderately strong polymerization conditions, the equilibrium state can contain both types of helical rods. The reaction volume for the addition of trimers is −220 ml/mol for both types of helical polymers. These results are compared with the results of previous thermodynamic analyses of TMVP polymerization.