Li Dianfan, Lee Jean, Caffrey Martin
Membrane Structural and Functional Biology Group, School of Biochemistry and Immunology, and School of Medicine, Trinity College, Dublin.
Cryst Growth Des. 2011;11(2):530-537. doi: 10.1021/cg101378s.
The default lipid for the bulk of the crystallogenesis studies performed to date using the cubic mesophase method is monoolein. There is no good reason however, why this 18-carbon, cis-monounsaturated monoacylglycerol should be the preferred lipid for all target membrane proteins. The latter come from an array of biomembrane types with varying properties that include hydrophobic thickness, intrinsic curvature, lateral pressure profile, lipid and protein makeup, and compositional asymmetry. Thus, it seems reasonable that screening for crystallizability based on the identity of the lipid creating the hosting mesophase would be worthwhile. For this, monoacylglycerols with differing acyl chain characteristics, such as length and olefinic bond position, must be available. A lipid synthesis and purification program is in place in the author's laboratory to serve this need. In the current study with the outer membrane sugar transporter, OprB, we demonstrate the utility of host lipid screening as a means for generating diffraction-quality crystals. Host lipid screening is likely to prove a generally useful strategy for mesophase-based crystallization of membrane proteins.
迄今为止，使用立方中间相方法进行的大部分晶体生成研究中，默认的脂质是单油酸甘油酯。然而，并没有充分的理由表明，这种18碳的顺式单不饱和单酰基甘油应该是所有目标膜蛋白的首选脂质。后者来自一系列具有不同特性的生物膜类型，这些特性包括疏水厚度、固有曲率、侧向压力分布、脂质和蛋白质组成以及组成不对称性。因此，基于形成主体中间相的脂质的特性来筛选可结晶性似乎是值得的。为此，必须有具有不同酰基链特征（如长度和烯键位置）的单酰基甘油。作者所在实验室已经建立了一个脂质合成和纯化程序来满足这一需求。在当前对外膜糖转运蛋白OprB的研究中，我们证明了主体脂质筛选作为生成衍射质量晶体的一种方法的实用性。主体脂质筛选可能是一种对基于中间相的膜蛋白结晶普遍有用的策略。
