Export of the siderophore enterobactin in Escherichia coli:: involvement of a 43 kDa membrane exporter
Export of the siderophore enterobactin in Escherichia coli:: involvement of a 43 kDa membrane exporter
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DOI：
10.1046/j.1365-2958.2002.02885.x
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发表时间：
2002-06-01
影响因子：
3.6
通讯作者：
McIntosh, MA
中科院分区：
文献类型：
--
作者：
Furrer, JL;Sanders, DN;McIntosh, MA
除了肠杆菌素分泌到细胞外环境的机制外，大肠杆菌中铁运输的肠杆菌素系统具有很好的特征。大肠杆菌膜蛋白P43编码于肠结合蛋白合成相关基因的染色体区域，与出口泵的12跨膜段主要促进因子超家族有很强的同源性。产生了一个p43零突变，对一组表达一个或多个肠杆菌素相关化合物的外膜受体的大肠杆菌进行了铁载体营养分析，结果表明p43突变体不能有效地分泌肠杆菌素。用薄层层析(TLC)和高效液相色谱(HPLC)对突变株释放的产物进行鉴定，发现突变株P43几乎不分泌肠杆菌素，但肠杆菌素分解产物2，3-二羟基苯甲酰丝氨酸(DHBs)单体、二聚体和三聚体水平升高。这些数据证实了P43是大肠杆菌肠杆菌素分泌机制的一个重要组成部分，并为将先前的遗传位点B bdA指定为Ents以反映其相关的生物学功能提供了理论依据。
The enterobactin system for iron transport in Escherichia coli is well characterized with the exception of the mechanism of enterobactin secretion to the extracellular environment. Escherichia coli membrane protein P43, encoded by ybdA in the chromosomal region of genes involved in enterobactin synthesis, shows strong homology to the 12-transmembrane segment major facilitator superfamily of export pumps. A P43-null mutation was created and siderophore nutrition assays, performed with a panel of E. coli strains expressing one or more outer membrane receptors for enterobactin-related compounds, demonstrated that the P43 mutant was unable to secrete enterobactin efficiently. Products released from the mutant strain were identified with thin-layer chromatography (TLC) and high-performance liquid chromatography (HPLC), revealing that the P43 mutant secretes little, if any, enterobactin, but elevated levels of enterobactin breakdown products 2,3- dihydroxybenzoylserine (DHBS) monomer, dimer, and trimer. These data establish that P43 is a critical component of the E. coli enterobactin secretion machinery and provides a rationale for the designation of the previous genetic locus ybdA as entS to reflect its relevant biological function.