Visualization of the redox condition in activating cells

氧化是重要的生化防御机制，但也会引起毒性；因此，必须严格控制氧化。在中性粒细胞的吞噬事件中，电压门控的H+通道是对抗入侵细菌产生活性氧的关键调节剂。在这项研究中，我们解决了电压门控H+通道在还原，氧化和突变（Cys到Ser）状态下的细胞质线圈结构。晶体结构表明，在二聚体线圈中，一对Cys残基在氧化还原条件下形成亚基间二硫键。圆二色光谱显示，二硫键增加了螺旋状蛋白的热稳定性。因此，我们发现电压门控H+通道在细胞质域具有氧化还原传感器。我们还尝试使用细胞内的线圈来监测氧化还原条件。

Oxidation is an important biochemical defense mechanism, but it also elicits toxicity; therefore, oxidation must be under strict control. In phagocytotic events in neutrophils, the voltage-gated H+ channel is a key regulator of the production of reactive oxygen species against invading bacteria. In this study, we solved the crystal structure of the cytoplasmic coiled-coil domain of the voltage-gated H+ channel in reduced, oxidized and mutated (Cys to Ser) states. The crystal structures indicated that a pair of Cys residues in the dimeric coiled-coil forms an intersubunit disulfide bond dependent on the redox conditions. Circular dichroism spectroscopy revealed that the disulfide bond increased the thermal stability of the coiled-coil protein. Thus, we revealed that the voltage-gated H+ channel has a redox-sensor in the cytoplasmic domain. We also tried to monitor the redox condition using the coiled-coil in cells.