BACTERIAL PHOSPHOENOLPYRUVATE-DEPENDENT PHOSPHOTRANSFERASE SYSTEM - ASSOCIATION STATE OF MEMBRANE-BOUND MANNITOL-SPECIFIC ENZYME-II DEMONSTRATED BY RADIATION INACTIVATION
BACTERIAL PHOSPHOENOLPYRUVATE-DEPENDENT PHOSPHOTRANSFERASE SYSTEM - ASSOCIATION STATE OF MEMBRANE-BOUND MANNITOL-SPECIFIC ENZYME-II DEMONSTRATED BY RADIATION INACTIVATION
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DOI：
10.1021/bi00395a019
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发表时间：
1987-10-20
期刊：
影响因子：
2.9
通讯作者：
ROBILLARD, GT
中科院分区：
文献类型：
--
作者：
PAS, HH;ELLORY, JC;ROBILLARD, GT
用辐射灭活方法研究了大肠杆菌细菌磷酸转移酶系统膜结合型甘露醇渗透酶(EIIMtl)的四级结构。实验揭示了两种截然不同但可相互转化的渗透酶形式。第一种状态是二聚体，第二种状态是由涉及二聚体的活性较低的较高分子量络合物组成。膜中这两种形态之间的平衡可以通过改变pH来改变。在pH值为8.1时，以二聚体为主。降低pH会增加调节蛋白与二聚体的结合，从而增加涉及二聚体的较高分子量形式的量。原位交联法、十二烷基硫酸钠-聚丙烯酰胺凝胶电泳法和免疫印迹法可形成两种交联型。一种是二聚体，另一种具有更高的分子质量。使用可逆交联剂的双向电泳显示，这些复合体中除了EIIMt1之外没有其他蛋白质。
The quaternary structure of the membrane-bound mannitol permease (EIIMtl) of the bacterial phosphotransferase system in Escherichia coli has been investigated in the membrane by using the radiation inactivation method. The experiments reveal two distinct but interconvertible forms of the permease. The first state is a dimer, and the second state consists of a less active higher molecular weight complex involving the dimer. The equilibrium between these two forms in the membrane can be shifted by changing the pH. At pH 8.1 the dimer is the dominant form. Decreasing the pH results in increased binding of a regulatory protein to the dimer, thus increasing the amount of the higher molecular weight form involving the dimer. Cross-linking EIIMtl in situ, followed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting, resulted in the formation of two cross-linked forms. One is the dimer, and the other has a higher molecular weight. Two-dimensional electrophoresis using a reversible cross-linker revealed no other protein except EIIMtl in these complexes.