Sandia National Laboratories, Livermore, California 94551, USA.
Langmuir. 2011 Feb 15;27(4):1457-62. doi: 10.1021/la1041458. Epub 2010 Dec 14.
We demonstrate the construction of novel protein-lipid assemblies through the design of a lipid-like molecule, DPIDA, endowed with tail-driven affinity for specific lipid membrane phases and head-driven affinity for specific proteins. In studies performed on giant unilamellar vesicles (GUVs) with varying mole fractions of dipalymitoylphosphatidylcholine (DPPC), cholesterol, and diphytanoylphosphatidyl choline (DPhPC), DPIDA selectively partitioned into the more ordered phases, either solid or liquid-ordered (L(o)) depending on membrane composition. Fluorescence imaging established the phase behavior of the resulting quaternary lipid system. Fluorescence correlation spectroscopy confirmed the fluidity of the L(o) phase containing DPIDA. In the presence of CuCl(2), the iminodiacetic acid (IDA) headgroup of DPIDA forms the Cu(II)-IDA complex that exhibits a high affinity for histidine residues. His-tagged proteins were bound specifically to domains enriched in DPIDA, demonstrating the capacity to target protein binding selectively to both solid and L(o) phases. Steric pressure from the crowding of surface-bound proteins transformed the domains into tubules with persistence lengths that depended on the phase state of the lipid domains.
我们通过设计一种类似脂质的分子 DPIDA 来构建新型的蛋白质-脂质组装体，该分子具有尾部驱动的对特定脂质膜相的亲和力和头部驱动的对特定蛋白质的亲和力。在对具有不同摩尔分数的二棕榈酰磷脂酰胆碱（DPPC）、胆固醇和二植烷酰基磷脂酰胆碱（DPhPC）的巨大单层囊泡（GUV）进行的研究中，DPIDA 选择性地分配到更有序的相中，具体取决于膜组成是固体相还是液晶相（L(o)）。荧光成像确定了所得四元脂质系统的相行为。荧光相关光谱证实了含有 DPIDA 的 L(o)相的流动性。在 CuCl2 的存在下，DPIDA 的亚氨基二乙酸（IDA）头基形成 Cu(II)-IDA 配合物，对组氨酸残基表现出高亲和力。His 标记的蛋白质特异性结合到富含 DPIDA 的域上，证明了有能力将蛋白质结合选择性地靶向固体相和 L(o)相。表面结合的蛋白质的拥挤产生的空间压力将这些域转化为具有依赖于脂质域相态的持久长度的管。
