ASSEMBLY OF SALMONELLA FLAGELLIN IN-VITRO AND IN-VIVO
ASSEMBLY OF SALMONELLA FLAGELLIN IN-VITRO AND IN-VIVO
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DOI：
10.1002/jss.400020226
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发表时间：
1974-01-01
期刊：
影响因子：
--
通讯作者：
LINO T
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文献类型：
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作者：
LINO T
从其组分蛋白质鞭毛蛋白形成沙门氏菌的鞭毛细丝原则上是一个自组装过程，其通过将鞭毛蛋白单体一个接一个地添加到细丝的远端来进行。当它们聚合时，鞭毛蛋白分子的构象发生变化，并且它赋予细丝极性。为了在生理离子强度和pH的溶液中引发体外鞭毛蛋白组装，必须添加鞭毛丝的片段，其作为鞭毛蛋白单体聚合的种子。当适当浓度的一些阴离子被称为良好的盐外层添加到溶液中时，聚合开始而不添加种子。鞭毛蛋白在体内的组装开始于每个钩的远端。无鞭毛蛋白突变体细胞上的钩的远端显示出在体外启动外源鞭毛蛋白的组装，尽管效率不如体内启动的效率高。只要提供足够量的鞭毛蛋白，鞭毛丝在体外以恒定速率伸长，并且伸长终止于在丝的生长端发生的错误。相反，在体内的伸长率随细丝长度的增加呈指数下降。在体内的初始伸长速率取决于细菌的生长条件，而每单位细丝长度的速率的下降受生长条件的影响很小。生长细菌上鞭毛丝长度的观察极限预期来自其伸长速率的指数下降。体内伸长的减少与鞭毛蛋白单体从细胞体通过鞭毛丝的中央管到尖端的运输效率的降低相关。
Formation of a flagellar filament of Salmonella from its component protein, flagellin, is in principle a self‐assembly process, which proceeds by the addition of flagellin monomers one by one to the distal end of the filament. Upon their polymerization, a conformational change of flagellin molecules occurs, and it confers polarity to the filament. For the initiation of in vitro flagellin assembly in a solution of physiological ionic strength and pH, it is essential to add fragments of flagellar filaments, which work as seeds for the polymerization of flagellin monomers. When an appropriate concentration of some anion known as a good salting‐outer is added to the solution, the polymerization begins without addition of seed. Assembly of flagellins in vivo begins at the distal end of each hook. The distal ends of the hooks on the cells of a flagellin‐less mutant were shown to initiate the assembly of exogenous flagellin in vitro, although the efficiency was not as high as that of the in vivo initiation. A flagellar filament elongates in vitro at a constant rate as long as a sufficient amount of flagellin is supplied, and the elongation terminates by an error occurring at the growing end of the filament. On the contrary, the rate of in vivo elongation decreases exponentially with increase of the length of the filament. Initial rate of the in vivo elongation depends on growth condition of the bacteria, while decrease of the rate per unit filament length is little affected by the growth condition. The observed limit in length of the flagellar filaments on growing bacteria is expected from the exponential decrease of their rate of elongation. The decrease of the in vivo elongation is correlated with the lowering of the transportation efficiency of flagellin monomers on their passage from the cell body through the central canal of a flagellar filament to the tip.