Involvement of stress protein PspA (phage shock protein A) of Escherichia coli in maintenance of the protonmotive force under stress conditions
Involvement of stress protein PspA (phage shock protein A) of Escherichia coli in maintenance of the protonmotive force under stress conditions
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DOI：
10.1002/j.1460-2075.1996.tb00344.x
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发表时间：
1996-01-02
期刊：
影响因子：
11.4
通讯作者：
Tommassen, J
中科院分区：
文献类型：
--
作者：
Kleerebezem, M;Crielaard, W;Tommassen, J
特异性PhoE突变蛋白的表达导致大肠杆菌psp操纵子表达的诱导，并且在pspA突变菌株中，各种质粒编码的前体的输出被延迟。我们已经研究了各种Psp蛋白在输出过程中的特定作用。PspB和PspC都是参与psp操纵子转录调控的内膜蛋白，前体PhoE易位在pspB突变株中被延迟到与pspA突变株中相似的程度，各种psp突变株中降低的易位效率可以通过从质粒表达PspA来补充，表明有效易位仅需要PspA，可以独立于Delta muH+转运的突变体prePhoE蛋白在野生型和pspA突变株中的转运效率似乎相同。此外，Δ mu H+的定量体内测定显示，在质粒编码的（突变体）prePhoE蛋白表达后，Δ mu H+在pspA突变体菌株中特异性降低。显然，在psp突变体菌株中观察到的易位缺陷是由Δ mu H+和PspA功能的降低引起的，通过在这些条件下维持Δ mu H+。
The expression of specific PhoE mutant proteins leads to induction of the expression of the psp operon of Escherichia coli and the export of various plasmid-encoded precursors is retarded in a pspA mutant strain, Here. we have investigated the specific role of various Psp proteins in the export process. PspB and PspC are both inner membrane proteins that are involved in the regulation of the transcription of the psp operon, Precursor PhoE translocation was retarded in a pspB mutant strain to a similar extent as in a pspA mutant strain, The reduced translocation efficiencies in the various psp mutants could be complemented by expression of PspA from a plasmid, indicating that only PspA is required for efficient translocation, Mutant prePhoE proteins that can be translocated independently of the Delta mu H+ appeared to translocate equally efficiently in a wild-type and in a pspA mutant strain. Furthermore, quantitative in vivo determination of the Delta mu H+ showed that it specifically decreased in a pspA mutant strain upon expression of plasmid-encoded (mutant) prePhoE protein, Apparently, the translocation defects observed in a psp mutant strain are caused by a decrease of the Delta mu H+ and PspA functions by maintaining the Delta mu H+ under these conditions.