A metrizamide-impermeable capsid in the DNA packaging pathway of bacteriophage T7.
A metrizamide-impermeable capsid in the DNA packaging pathway of bacteriophage T7.
复制标题
噬菌体 T7 的 DNA 包装途径中的甲磺酰胺不可渗透的衣壳。
DOI：
10.1016/s0022-2836(80)80005-2
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发表时间：
1980
影响因子：
5.6
通讯作者：
P. Serwer
中科院分区：
文献类型：
--
作者：
P. Serwer
来自噬菌体T7感染的大肠杆菌的裂解物的衣壳在甲泛葡胺密度梯度中进行浮力密度沉降。T7衣壳的一些颗粒以前称为衣壳II（Serwer，1976），密度为1.275 g/cm 3（甲泛葡胺高密度衣壳II或MHD衣壳II），其他颗粒的密度为1.086至1.100 g/cm 3（甲泛葡胺低密度衣壳II或MLD衣壳II）。氯化铯密度梯度中MHD和MLD衣壳II的密度表明，MLD衣壳II在甲泛葡胺梯度中的密度低于MHD衣壳II，因为MLD衣壳II的优先溶剂化Γ′（2.4至1.9 g/g）高于MHD衣壳II的Γ′（0.25 g/g）。数据表明，MLD衣壳II的较高Γ′的出现是因为MLD衣壳II的包膜是不可渗透的，而MHD衣壳II的包膜对甲泛葡胺是可渗透的。电子显微镜显示，大多数MLD衣壳II颗粒具有内部圆柱形核心，而大多数MHD衣壳II颗粒则没有。动力学标记实验的结果表明，MLD和MHD衣壳II的前体噬菌体T7的衣壳或这种前体的降解产物。MLD衣壳II和MHD衣壳II已通过使用非变性条件的琼脂糖凝胶电泳、十二烷基硫酸钠/聚丙烯酰胺凝胶电泳和速度沉降进行表征。
Capsids from lysates of bacteriophage T7-infectedEscherichia colihave been subjected to buoyant density sedimentation in metrizamide density gradients. Some particles of a T7 capsid previously referred to as capsid II (Serwer, 1976) had a density of 1·275 g/cm3(metrizamide high-density capsid II or MHD capsid II) and others had a density of 1·086 to 1·100 g/cm3(metrizamide lowdensity capsid II or MLD capsid II). The densities of MHD and MLD capsids II in cesium chloride density gradients indicate that MLD capsid II has a lower density than MHD capsid II in metrizamide gradients because the preferential solvation,Γ′, of MLD capsid II (2·4 to 1·9 g/g) is higher than theΓ′ of MHD capsid II (0·25 g/g). Data are presented indicating that the higherΓ′ of MLD capsid II occurs because the envelope of MLD capsid II is impermeable and the envelope of MHD capsid II is permeable to metrizamide.Electron microscopy revealed that most MLD capsid II particles had an internal, cylindrical core and that most MHD capsid II particles did not. The results of kinetic labeling experiments suggest that MLD and MHD capsids II are either precursors to the capsid of bacteriophage T7 or degradation products of such precursors. MLD capsid II and MHD capsid II have been characterized by electrophoresis in agarose gels using non-denaturing conditions, sodium dodecyl sulfate/polyacrylamide gel electrophoresis and velocity sedimentation.