Grant Chris F, Kanda Vishal, Yu Henry, Bundle David R, McDermott Mark T
Department of Chemistry and National Institute for Nanotechnology, University of Alberta, Edmonton, AB, Canada.
Langmuir. 2008 Dec 16;24(24):14125-32. doi: 10.1021/la8026489.
The interactions between proteins and immobilized carbohydrates are crucial to biological events such as cell signaling and immune response. The modification of surfaces with carbohydrates to create sensing platforms provides a pathway to study these interactions in a laboratory setting. In this work, a family of structurally related Salmonella disaccharide epitopes is immobilized on thin gold films in an array format to probe antibody binding with surface plasmon resonance (SPR) imaging. The disaccharides are modified with an alkyl thiol linker for facile immobilization to gold. Small differences in the stereochemistry of the immobilized, modified disaccharides are shown to greatly influence the binding of a monoclonal antibody. Specifically, binding is only observed to an immobilized abequose dideoxyhexose relative to a tyvelose or a paratose analogue. However, both the amount and relative strength of bound antibody depends on the distribution of disaccharide moieties in a mixed monolayer of the epitope and a nonbinding diluent molecule. We thoroughly characterize the mixed monolayers with a variety of techniques to understand the optimal density and distribution of the disaccharide for antibody capture. This work reinforces the importance of controlling the density of ligands at the interface for optimized surface based bioassays.
蛋白质与固定化碳水化合物之间的相互作用对于诸如细胞信号传导和免疫反应等生物学事件至关重要。用碳水化合物修饰表面以创建传感平台为在实验室环境中研究这些相互作用提供了一条途径。在这项工作中，一族结构相关的沙门氏菌二糖表位以阵列形式固定在薄金膜上，以通过表面等离子体共振（SPR）成像探测抗体结合。二糖用烷基硫醇连接子进行修饰，以便于固定到金上。结果表明，固定化修饰二糖的立体化学上的微小差异会极大地影响单克隆抗体的结合。具体而言，相对于泰威糖或副鼠李糖类似物，仅观察到抗体与固定化的阿比可糖（一种脱氧己糖）结合。然而，结合抗体的量和相对强度均取决于表位与非结合稀释剂分子的混合单分子层中二糖部分的分布。我们用多种技术全面表征了混合单分子层，以了解用于抗体捕获的二糖的最佳密度和分布。这项工作强化了在界面处控制配体密度对于优化基于表面的生物测定的重要性。
