A major obstacle to elucidating the structure of membrane proteins at high resolution is the difficulty of preparing these proteins as well as to grow well-ordered crystals. During the last few years several groups have considered the use of three-dimensional bicontinuous lipidic cubic phases as a possible crystallization matrix for such molecules. In a few cases these studies have been successfully approached by other laboratories, however, a number of questions remain, particularly in regard to the effects of solutes on the phase diagrams of lipid-water systems. In the present work we report the structural behavior of the lipidic Q224 (Pn3m), Q230 (Ia3d) and HII phases systematically studied in the presence of a range of concentrations of various salts and precipitating agents at various pH values. Some of the results reported here have been presented elsewhere Vargas et al. (2000) [Strategies in membrane protein crystallization. Chemical Prospectives in Crystallography of Molecular Biology. International School of Crystallography, NATO-ASI course, Erice (Italy)].

中文翻译：

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用于使蛋白质结晶的沉淀盐浓度增加对脂质Q224立方相结构的影响。

高分辨率阐明膜蛋白结构的主要障碍是难以制备这些蛋白以及难以生长有序晶体。在最近几年中，几个小组已经考虑使用三维双连续脂质立方相作为此类分子的可能结晶基质。在少数情况下，这些研究已被其他实验室成功进行，但是仍然存在许多问题，尤其是关于溶质对脂质-水系统相图的影响。在本工作中，我们报告了在各种pH值范围内的各种盐和沉淀剂的浓度范围内，系统地研究了脂质Q224（Pn3m），Q230（Ia3d）和HII相的结构行为。此处报道的一些结果已在Vargas等人的文章中进行了介绍。（2000）[膜蛋白结晶的策略。分子生物学晶体学中的化学前景。国际晶体学学院，北约ASI课程，埃里塞（意大利）]。