Andrä Jörg, Böhling Arne, Gronewold Thomas M A, Schlecht Ulrich, Perpeet Markus, Gutsmann Thomas
Research Center Borstel, Division of Biophysics, Parkallee 10, Borstel, Germany.
Langmuir. 2008 Aug 19;24(16):9148-53. doi: 10.1021/la801252t. Epub 2008 Jul 8.
Surface acoustic wave biosensors are a powerful tool for the study of biomolecular interactions. The modulation of a surface-confined acoustic wave is utilized here for the analysis of surface binding. Phase and amplitude of the wave correspond roughly to mass loading and viscoelastic properties of the surface, respectively. We established a procedure to reconstitute phospholipid and lipopolysaccharide bilayers on the surface of a modified gold sensor chip to study the mode of action of membrane-active peptides. The procedure included the formation of a self-assembled monolayer of 11-mercaptoundecanol, covalent coupling of carboxymethyl-dextran, and subsequent coating with a poly- l-lysine layer. The lipid coverage of the surface is highly reproducible and homogeneous as demonstrated in atomic force micrographs. Ethanol/triton treatment removed the lipids completely, which provided the basis for continuous sequences of independent experiments. The setup was applied to investigate the binding of human cathelicidin-derived peptide LL32, as an example for antimicrobial peptides, to immobilized phosphatidylserine membranes. The peptide-membrane interaction results in a positive phase shift and an increase in amplitude, indicating a mass increase along with a loss in viscosity. This suggests that the bilayer becomes more rigid upon interaction with LL32.
表面声波生物传感器是研究生物分子相互作用的有力工具。这里利用表面受限声波的调制来分析表面结合。波的相位和幅度分别大致对应于表面的质量负载和粘弹性特性。我们建立了一种在修饰的金传感器芯片表面重构磷脂和脂多糖双层的方法，以研究膜活性肽的作用模式。该方法包括形成11-巯基十一醇的自组装单层、羧甲基葡聚糖的共价偶联，以及随后用聚-L-赖氨酸层进行包被。如原子力显微镜图像所示，表面的脂质覆盖具有高度的可重复性和均匀性。乙醇/曲拉通处理完全去除了脂质，这为连续进行独立实验提供了基础。以人源cathelicidin衍生肽LL32（一种抗菌肽）与固定化磷脂酰丝氨酸膜的结合为例，应用该装置进行了研究。肽与膜的相互作用导致正相移和幅度增加，表明质量增加且粘度降低。这表明双层在与LL32相互作用时变得更加刚性。
