Distinct sensitivities of OmpF and PhoE porins to charged modulators.
Distinct sensitivities of OmpF and PhoE porins to charged modulators.
复制标题
OmpF 和 PhoE 孔蛋白对带电调节剂具有不同的敏感性。
DOI：
10.1016/s0014-5793(99)00030-7
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发表时间：
1999
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：
Samartzidou,H;Delcour,AH
之前已经记录了ATP对阴离子选择性PhoE孔蛋白的抑制和多胺对阳离子选择性OmpF孔蛋白的抑制。在本研究中，我们已经扩展了比较的通道-孔蛋白对调查的影响阴离子（ATP和天冬氨酸）和带正电的多胺（精胺和尸胺）的OmpF和PhoE与膜片钳技术，并通过比较直接的门控动力学的通道调制各自的基板。本文报道的新发现是：（1）PhoE的活性完全不受多胺的影响，（2）ATP对PhoE或多胺对OmpF诱导的动力学变化表明不同的抑制机制。ATP在PhoE介导的电流中诱导高度的闪烁，并且似乎在其通过PhoE的假定运输期间表现为离子流的阻断剂。多胺调节OmpF的开放和关闭的动力学，除了促进阻断剂样闪烁活性。对抑制剂的敏感性和离子选择性之间的强相关性表明，一些共同的分子决定因素参与这两个属性，并与多胺结合阳离子孔蛋白的孔内的假设是一致的。
The inhibition of the anion-selective PhoE porin by ATP and of the cation-selective OmpF porin by polyamines has been previously documented. In the present study, we have extended the comparison of the inhibitor-porin pairs by investigating the effect of anions (ATP and aspartate) and positively charged polyamines (spermine and cadaverine) on both OmpF and PhoE with the patch-clamp technique, and by comparing directly the gating kinetics of the channels modulated by their respective substrates. The novel findings reported here are (1) that the activity of PhoE is completely unaffected by polyamines, and (2) that the kinetic changes induced by ATP on PhoE or polyamines on OmpF suggest different mechanisms of inhibition. ATP induces a high degree of flickering in the PhoE-mediated current and appears to behave as a blocker of ion flow during its presumed transport through PhoE. Polyamines modulate the kinetics of openings and closings of OmpF, in addition to promoting a blocker-like flickering activity. The strong correlation between sensitivity to inhibitors and ion selectivity suggests that some common molecular determinants are involved in these two properties and is in agreement with the hypothesis that polyamines bind inside the pore of cationic porins.