Aizawa S I, Kato S, Asakura S, Kagawa H, Yamaguchi S
Biochim Biophys Acta. 1980 Oct 21;625(2):291-303. doi: 10.1016/0005-2795(80)90293-7.
Polyhooks were isolated from Salmonella SJW880, a non-flagellated mutant, and purified by cesium chloride density gradient centrifugation. The polyhooks were disintegrated into protein subunits (monomer) by heat in the absence of salt. The monomer was repolymerized in the presence of moderately high concentrations of sodium citrate at neutral pH. Three types of polymer were produced. One type of polymer, produced at room temperature and at citrate concentrations less than 0.3 M, had no regular shape and no definite thickness. Another type of polymer, produced at room temperature and at citrate concentrations greater than 0.4 M, had a straight shape and a similar thickness to that of polyhook but was easily dissociated into monomer in the absence of salt. A third type of polymer was produced at low temperature, independently of the concentration of citrate, and seemed to be a tubular polymer with a thickness similar to that of polyhook but had no helical curvature. However, this type of polymer was shown to have a structure locally the same as that of polyhook by electron microscopic observation, optical diffraction and circular dichroism measurements.
多钩蛋白从无鞭毛突变体沙门氏菌SJW880中分离出来，并通过氯化铯密度梯度离心法进行纯化。在无盐条件下，通过加热将多钩蛋白分解为蛋白质亚基（单体）。在中性pH值下，在中等浓度的柠檬酸钠存在下，单体重新聚合。产生了三种类型的聚合物。一种聚合物在室温下且柠檬酸盐浓度低于0.3 M时产生，没有规则形状且没有确定的厚度。另一种聚合物在室温下且柠檬酸盐浓度大于0.4 M时产生，呈直线状，厚度与多钩蛋白相似，但在无盐条件下很容易解离成单体。第三种聚合物在低温下产生，与柠檬酸盐浓度无关，似乎是一种管状聚合物，厚度与多钩蛋白相似，但没有螺旋曲率。然而，通过电子显微镜观察、光学衍射和圆二色性测量表明，这种类型的聚合物局部结构与多钩蛋白相同。
