合成纳米盘是小尺寸的盘状结构体,由细胞膜磷脂组成,而磷脂则通过合成聚合物环结合在一起。
图 1:合成纳米盘描述
纳米盘提供了细胞膜中天然膜蛋白环境的可迁移、几乎一致的复制品。因此,它们规避了增溶去污剂的问题,使我们能够在活性状态下保持膜蛋白稳定或对其进行分离,以便开展进一步的科学研究。 |
有几种不同的聚合物可用于制造合成纳米盘,各有其优缺点。
合成聚合物如何形成所需的纳米盘?
细胞膜为最重要的蛋白质组之一提供了其所需的环境:膜蛋白质组。膜蛋白分为外周蛋白和整合蛋白两种,二者均具有一定的疏水性,在正常条件下不易溶解。
问题是,当这些疏水区与水或其他亲水性介质接触时,膜蛋白的 3D 结构将坍塌,从而失去其功能性。
为避免这种情况发生,蛋白质研究科学家通常使用去污剂(洗涤剂)来覆盖膜蛋白的这些脆弱部分。但由于使用去污剂的方法也有其自身的一系列问题,如筛选过程耗时长或3D 结构的干扰等情况。
相比之下,合成聚合物能够从其单体中形成聚合物链,插入所需的目标膜蛋白周围的细胞膜之中(见图2,顶部红线)。像饼干模具(cookie cutter)一样,将膜蛋白从膜中溶解出来,而聚合物则使膜蛋白在新形成的纳米盘中保持稳定。
接下来采用亲和层析法精确分离稳定的目标蛋白,并实施进一步的科学分析。
图2:在包含膜蛋白的天然细胞膜中制备合成纳米盘的过程。下一个步骤一般为亲和层析。
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