Sir William Dunn School of Pathology, University of Oxford , Oxford OX1 3RE, UK.
Open Biol. 2011 Nov;1(3):110010. doi: 10.1098/rsob.110010.
Redox conditions change in events such as immune and platelet activation, and during viral infection, but the biochemical consequences are not well characterized. There is evidence that some disulfide bonds in membrane proteins are labile while others that are probably structurally important are not exposed at the protein surface. We have developed a proteomic/mass spectrometry method to screen for and identify non-structural, redox-labile disulfide bonds in leucocyte cell-surface proteins. These labile disulfide bonds are common, with several classes of proteins being identified and around 30 membrane proteins regularly identified under different reducing conditions including using enzymes such as thioredoxin. The proteins identified include integrins, receptors, transporters and cell-cell recognition proteins. In many cases, at least one cysteine residue was identified by mass spectrometry as being modified by the reduction process. In some cases, functional changes are predicted (e.g. in integrins and cytokine receptors) but the scale of molecular changes in membrane proteins observed suggests that widespread effects are likely on many different types of proteins including enzymes, adhesion proteins and transporters. The results imply that membrane protein activity is being modulated by a 'redox regulator' mechanism.
氧化还原条件会在免疫和血小板激活等事件以及病毒感染期间发生变化，但生化后果尚未得到很好的描述。有证据表明，膜蛋白中的一些二硫键不稳定，而其他可能对结构很重要的二硫键则没有暴露在蛋白质表面。我们已经开发了一种蛋白质组学/质谱方法，用于筛选和鉴定白细胞细胞表面蛋白中的非结构、氧化还原不稳定的二硫键。这些不稳定的二硫键很常见，已经鉴定出几类蛋白质，并且在不同的还原条件下（包括使用硫氧还蛋白等酶）经常鉴定出约 30 种膜蛋白。鉴定出的蛋白质包括整合素、受体、转运蛋白和细胞间识别蛋白。在许多情况下，通过质谱至少鉴定出一个半胱氨酸残基被还原过程修饰。在某些情况下，预测会发生功能变化（例如整合素和细胞因子受体），但观察到的膜蛋白中分子变化的规模表明，包括酶、粘附蛋白和转运蛋白在内的许多不同类型的蛋白质都可能受到广泛影响。这些结果表明，膜蛋白活性受到“氧化还原调节剂”机制的调节。
