Genetic analysis of the colicin V secretion pathway.
Genetic analysis of the colicin V secretion pathway.
复制标题
大肠菌素 V 分泌途径的遗传分析。
DOI：
10.1093/genetics/141.1.25
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发表时间：
1995
期刊：
影响因子：
3.3
通讯作者：
Kolter,R
中科院分区：
文献类型：
--
作者：
Zhang,LH;Fath,MJ;Mahanty,HK;Tai,PC;Kolter,R
结肠素V(Colicin V，COLV)是一种由大肠杆菌通过CVAA、Cva B和TolC三种蛋白组成的专用输出子分泌的多肽抗生素。COLV的分泌独立于大肠杆菌总分泌途径(SEC)，但需要CvaAB/TolC输出子特有的N端输出信号。用遗传学和生物化学方法对COLV的分泌进行鉴定。当COLV N-末端延伸被OmpA信号序列取代时，SEC系统可以将COLV定位到周质。周质COLV对缺乏COLV免疫蛋白CVI的细胞是致命的。基于这一结果，设计了一种基因检测方法来监测正常CvaAB/TolC介导的分泌过程中周质COLV的存在。结果表明，在分泌过程中，周质中可能存在低水平的COLV。用免疫沉淀法还鉴定了来自野生型系统和不同输出子突变背景的前体和成熟COLV。COLV在野生型细胞中的处理速度很快，CVAA和CvaB是发生处理的关键。相反，在TolC突变体中，处理过程正常进行，尽管速度较慢。
Colicin V (ColV) is peptide antibiotic secreted by Escherichia coli through a dedicated exporter composed of three proteins, CvaA, CvaB, and TolC. ColV secretion is independent of the E. coli general secretory pathway (Sec) but requires an N-terminal export signal specific for the CvaAB/TolC exporter. ColV secretion was characterized using genetic and biochemical methods. When the ColV N-terminal extension is replaced with the OmpA signal sequence, the Sec system can localize ColV to the periplasm. Periplasmic ColV is lethal to cells lacking the ColV immunity protein, Cvi. Based on this result, a genetic assay was designed to monitor for the presence of periplasmic ColV during normal CvaAB/TolC mediated secretion. Results indicate that low levels of ColV may be present in the periplasm during secretion. Precursor and mature ColV were also characterized from the wild-type system and in various exporter mutant backgrounds using immunoprecipitation. ColV processing is rapid in wild-type cells, and CvaA and CvaB are critical for processing to occur. In contrast, processing occurs normally, albeit more slowly, in a TolC mutant.