The preparation of cell membranes by ultracentrifugation of bacterial cell lysates, a pre-requisite for the purification of over-expressed membrane proteins, is both time-consuming and difficult to perform on a large scale. To overcome this bottleneck in the structural investigation of such proteins in the UK Membrane Protein Structure Initiative, we have investigated the alternative use of tangential flow filtration for preparation of membranes from Escherichia coli. This method proved to be superior to the conventional use of ultracentrifuges both in speed and in yield of membrane protein. Moreover, it could more readily be scaled up to process larger quantities of bacterial cells. Comparison of the purity and monodispersity of an over-expressed membrane protein purified from conventionally-prepared membranes and from membranes prepared by filtration revealed no substantial differences. The approach described should therefore be of general use for membrane protein preparation for a wide range of applications, including both structural and functional studies.

中文翻译：

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通过切向流过滤大规模制备细菌细胞膜。

通过细菌细胞裂解物的超速离心制备细胞膜是纯化过表达的膜蛋白的先决条件，既费时又难以大规模进行。为了克服英国膜蛋白结构计划中此类蛋白的结构研究中的瓶颈，我们研究了切向流过滤用于从大肠杆菌制备膜的替代用途。事实证明，该方法在速度和膜蛋白产量方面均优于传统的超速离心机。而且，它可以更容易地按比例放大以处理大量细菌细胞。从常规制备的膜和通过过滤制备的膜纯化的过表达膜蛋白的纯度和单分散性的比较显示没有实质性差异。因此，所描述的方法应普遍用于膜蛋白的制备，以用于广泛的应用，包括结构和功能研究。