Role of acidic lipids in the translocation and channel activity of colicins A and N in Escherichia coli cells.
Role of acidic lipids in the translocation and channel activity of colicins A and N in Escherichia coli cells.
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酸性脂质在大肠杆菌细胞中大肠杆菌素 A 和 N 的易位和通道活性中的作用。
DOI：
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发表时间：
1993
期刊：
影响因子：
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通讯作者：
L. Letellier
中科院分区：
文献类型：
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作者：
F. G. van der Goot;N. Didat;F. Pattus;W. Dowhan;L. Letellier
大肠杆菌素A和N是能杀死大肠杆菌细胞的成孔细菌毒素。它们的作用模式涉及三个步骤：与位于外膜的特异性受体结合，通过该膜和周质移位，以及在内膜中形成通道。体外研究表明，带负电荷的磷脂是大肠杆菌素A通道形成的绝对必要条件。使用HDL 11菌株，其中通过改变PtdGro-磷酸合酶的合成来改变磷脂酰甘油（PtdGro）含量，在体内研究了包膜PtdGro含量对大肠杆菌素A活性的影响。大肠杆菌素A在细胞质膜上形成电压门控通道，导致细胞质钾外流。这种流出之前有一个滞后时间，这与毒素穿过细胞包膜所需的时间有关。当细胞具有降低的PtdGro水平时，该滞后时间更高，表明大肠杆菌素A（OmpF、BtuB和Tol QRAB蛋白）的受体/易位机制在PtdGro不存在的情况下改变。当PtdGro含量降低时，钾流出的速率也大大降低，这表明一定水平的PtdGro确实是正确插入大肠杆菌素-A通道所必需的。相反，大肠杆菌素N的活性不显示任何PtdGro依赖性。讨论了大肠杆菌素A和大肠杆菌素N的行为差异。
Colicins A and N are pore-forming bacterial toxins that kill Escherichia coli cells. Their mode of action involves three steps; binding to specific receptors located in the outer membrane, translocation through this membrane and the periplasm, and channel formation in the inner membrane. In-vitro studies have shown that negatively charged phospholipids are an absolute requirement for the channel formation of colicin A. Using HDL11 strain, in which the phosphatidylglycerol (PtdGro) content was altered by varying the synthesis of the PtdGro-phosphate synthase, the effect of envelope PtdGro content on the activity of colicin A was studied in vivo. The formation by colicin A of a voltage-gated channel in the cytoplasmic membrane results in an efflux of cytoplasmic potassium. This efflux is preceded by a lag time which is related to the time needed by the toxin to cross the cell envelope. This lag time is higher when the cells have a reduced PtdGro level, suggesting that the receptor/translocation machinery of colicin A (OmpF, BtuB and Tol QRAB proteins) is altered in the absence of PtdGro. The rate of potassium efflux is also greatly reduced when the PtdGro content is decreased, suggesting that a certain level of PtdGro is indeed required for proper insertion of the colicin-A channel. In contrast, the activity of colicin N does not show any PtdGro dependence. The difference between the behavior of colicin A and that of colicin N is discussed.
大肠菌素 E1 及其 COOH 末端胰蛋白酶肽的宏观和单通道电导特性的比较。
DOI：
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发表时间：
1983
期刊：
The Journal of biological chemistry
影响因子：
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作者：
Bullock,JO;Cohen,FS;Dankert,JR;Cramer,WA
通讯作者：
Cramer,WA
阴离子磷脂和部分解折叠可促进部分大肠杆菌 SecA 蛋白深入渗透到模型膜中。
DOI：
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发表时间：
1992
期刊：
The Journal of biological chemistry
影响因子：
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作者：
Ulbrandt,ND;London,E;Oliver,DB
通讯作者：
Oliver,DB