pH-Dependent Gating in a FocA Formate Channel
pH-Dependent Gating in a FocA Formate Channel
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DOI：
10.1126/science.1199098
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发表时间：
2011-04-15
期刊：
影响因子：
56.9
通讯作者：
Einsle, Oliver
中科院分区：
文献类型：
--
作者：
Lue, Wei;Du, Juan;Einsle, Oliver
甲酸盐转运蛋白 FocA 被描述为将其操作模式从高外部 pH 值下的被动输出通道转换为低 pH 值下的次级活性甲酸盐/H+ 输入通道。 pH 4.0 时鼠伤寒沙门氏菌 FocA 的晶体结构表明，这种转换涉及五聚体通道中各个原聚体的氨基末端的主要重排。氨基末端螺旋以协调一致的协同作用打开或阻断转运，这表明 FocA 如何以 pH 依赖性方式门控。电生理学研究表明，该蛋白质在 pH 7.0 时充当特定的甲酸通道，并在 pH 值升至 5.1 时关闭。
The formate transporter FocA was described to switch its mode of operation from a passive export channel at high external pH to a secondary active formate/H+ importer at low pH. The crystal structure of Salmonella typhimurium FocA at pH 4.0 shows that this switch involves a major rearrangement of the amino termini of individual protomers in the pentameric channel. The amino-terminal helices open or block transport in a concerted, cooperative action that indicates how FocA is gated in a pH-dependent way. Electrophysiological studies show that the protein acts as a specific formate channel at pH 7.0 and that it closes upon a shift of pH to 5.1.