Zorzopulos J, DeLong S, Chapman V, Kozloff L M
J Bacteriol. 1980 Jun;142(3):982-91. doi: 10.1128/jb.142.3.982-991.1980.
A variety of degradative treatments have been used to investigate the nature of the structure and components of the cell walls of Escherichia coli B. The binding and localization of the endotoxin-like particles found on the cell walls were of special interest because some of them are associated with the site where the inner tail tube of bacteriophage T4D penetrates the cell wall. Modified cell walls were obtained by heating a suspension of bacterial cells originally in 0.1 M phosphate, pH 7.0, after the addition of 12.5 M NaOH to a final concentration of 0.25 M. With regard to the endotoxin-like particles, it was found that: (i) at least part of them still remained bound to the modified cell wall after the alkali treatment; (ii) the subsequent incubation of alkali-treated cell walls with lysozyme destroyed the bacterial form and released a complex of endotoxin-like particles together with a fibrous material; (iii) on the other hand, treatment with 45% phenol at 70 degrees C removed the endotoxin-like particles from the surface of the alkali-treated cell walls, but most of the fibrous material was left on the cell wall; and (iv) incubation of alkali-treated cell walls with 5 mM ethylenediaminetetraacetic acid at 20 degrees C also removed the endotoxin-like particles, but did not disrupt the rodlike bacterial form. However, if the ethylenediaminetetraacetic acid treatment was performed at 55 degrees C, the bacterium-like form was destroyed. These differential sensitivities to ethylenediaminetetraacetic acid suggested that loosely bound divalent metal ions normally hold these endotoxin-like particles on the cell wall surface, but that probably more tightly bound metal ions are involved in the determination of cell shape. Analysis of the protein components of the alkalitreated cell walls showed that only one protein was present in significant amounts, and this protein had an electrophoretic mobility similar to that of the Braun lipoprotein. This protein was released from the alkali-treated cell walls upon heating with 2% sodium dodecyl sulfate at 100 degrees C. Phospholipids were also absent from this structure. The distribution of the remaining cell wall components on the alkali-treated cell walls is discussed.
已采用多种降解处理方法来研究大肠杆菌B细胞壁的结构和成分的性质。细胞壁上发现的类内毒素颗粒的结合和定位特别令人感兴趣，因为其中一些颗粒与噬菌体T4D的内尾管穿透细胞壁的部位有关。在最初处于0.1 M磷酸盐（pH 7.0）的细菌细胞悬浮液中加入12.5 M NaOH至最终浓度为0.25 M后，通过加热获得修饰的细胞壁。关于类内毒素颗粒，发现：（i）碱处理后，至少部分颗粒仍与修饰的细胞壁结合；（ii）碱处理后的细胞壁随后与溶菌酶孵育会破坏细菌形态，并释放出类内毒素颗粒与纤维状物质的复合物；（iii）另一方面，在70℃用45%苯酚处理可从碱处理的细胞壁表面去除类内毒素颗粒，但大部分纤维状物质留在细胞壁上；（iv）在20℃用5 mM乙二胺四乙酸孵育碱处理的细胞壁也可去除类内毒素颗粒，但不会破坏杆状细菌形态。然而，如果在55℃进行乙二胺四乙酸处理，则细菌形态会被破坏。这些对乙二胺四乙酸的不同敏感性表明，通常松散结合的二价金属离子将这些类内毒素颗粒保持在细胞壁表面，但可能更紧密结合的金属离子参与细胞形状的确定。对碱处理细胞壁的蛋白质成分分析表明，只有一种蛋白质大量存在，且该蛋白质的电泳迁移率与布劳恩脂蛋白相似。在100℃用2%十二烷基硫酸钠加热时，该蛋白质从碱处理的细胞壁中释放出来。该结构中也不存在磷脂。讨论了碱处理细胞壁上其余细胞壁成分的分布。
