Inhibitory effect of acidic pH on OmpC porin: wild-type and mutant studies.
Inhibitory effect of acidic pH on OmpC porin: wild-type and mutant studies.
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酸性 pH 对 OmpC 孔蛋白的抑制作用：野生型和突变体研究。
DOI：
10.1016/s0014-5793(98)00975-2
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发表时间：
1998
期刊：
影响因子：
3.5
通讯作者：
Delcour,AH
中科院分区：
文献类型：
--
作者：
Liu,N;Delcour,AH
通过使用的膜片钳技术，我们比较了OmpC孔蛋白通道在中性和酸性pH值的电生理特征。灌注pH 5.4缓冲液的周质侧切除补丁促进关闭或块的20%的开放孔蛋白存在于补丁中，而不改变其单通道电导。除了对主要的长寿命开放状态的这种影响之外，降低pH还抑制通道向另一种不同的短寿命开放状态的自发转变。对开放动力学的抑制作用在两种突变体（K16Q和E109Q）中特别明显，其中在pH 7.2下突变本身增强了向短暂开放状态的转变。另一方面，R124Q突变体响应于酸性pH，通过增加门控到短暂的开放状态。结果表明，酸性pH稳定了OmpC孔蛋白的封闭状态，并且pH敏感性可能部分由R124赋予，而不是由K16或E109赋予。
By use of the patch clamp technique, we have compared the electrophysiological signature of OmpC porin channels at neutral and acidic pH. The perfusion of pH 5.4 buffer to the periplasmic side of excised patches promoted the closure or block of ∼20% of the open porins present in the patch without changes in their single channel conductance. Besides this effect on the main, long-lived open state, lowering the pH also suppressed the spontaneous transitions of channels to another distinct short-lived open state. The inhibitory effect on the opening kinetics was particularly visible in two mutants (K16Q and E109Q) in which transitions to the short-lived open state are enhanced by the mutations themselves at pH 7.2. On the other hand, the R124Q mutant responded to acidic pH by an increased gating to the short-lived open state. The results suggest that acidic pH stabilizes a closed state of OmpC porin, and that the pH sensitivity might be conferred in part by R124, but not by K16 or E109.