Japan Chemical Innovation Institute, 1-3-5 Jimbocho, Chiyoda-ku, Tokyo 101-0051, Japan.
J Colloid Interface Sci. 2013 Mar 1;393:257-63. doi: 10.1016/j.jcis.2012.10.056. Epub 2012 Nov 8.
The immobilization of carbohydrates on gold surfaces is a prerequisite technology for carbohydrate-related studies, including those of carbohydrate-biomolecule interactions. Glycolipid domains in cell membranes, such as lipid rafts, are thought to play an important role in cell biology through their carbohydrate portions. To understand the recognition of glycolipid domains such as receptors for bacterial toxins and viruses, we immobilized clusters of carbohydrates on a gold surface by using polyamidoamine (PAMAM) dendrimers as a scaffold. The PAMAM dendrimers were adsorbed on the gold-coated surface of a quartz crystal microbalance (QCM) sensor and were observed by means of QCM with dissipation (QCM-D). After adsorption of the PAMAM dendrimers, lysoganglioside-GM(1) and 12-aminododecyl-N-acetylglucosaminide (GlcNAc-C12-NH(2)) were immobilized on the amino groups of PAMAM dendrimers by means of an NH(2) cross-linker. Immobilization of the carbohydrates was confirmed by observation of their specific interaction with anti-ganglioside GM(1) antibody or wheat germ agglutinin (WGA). Surfaces with different GlcNAc-C12-NH(2) cluster sizes and densities were prepared by varying the size of the PAMAM dendrimers or the concentration of GlcNAc-C12-NH(2) immobilized on the dendrimers, respectively. Analysis of the binding between the GlcNAc-C12-NH(2)-immobilized surface and WGA revealed that the size of the PAMAM dendrimers influenced the GlcNAc-C12-NH(2)-WGA interaction, with larger dendrimers resulting in higher WGA binding constants.
碳水化合物在金表面的固定化是碳水化合物相关研究的前提技术，包括碳水化合物-生物分子相互作用的研究。细胞膜中的糖脂域，如脂筏，被认为通过其碳水化合物部分在细胞生物学中发挥重要作用。为了理解糖脂域（如细菌毒素和病毒的受体）的识别，我们使用聚酰胺-胺（PAMAM）树枝状大分子作为支架将碳水化合物簇固定在金表面上。PAMAM 树枝状大分子被吸附在石英晶体微天平（QCM）传感器的镀金表面上，并通过 QCM 与耗散（QCM-D）进行观察。PAMAM 树枝状大分子吸附后，溶神经节苷脂-GM(1)和 12-氨基十二烷基-N-乙酰氨基葡萄糖胺（GlcNAc-C12-NH(2)）通过 NH(2)交联剂固定在 PAMAM 树枝状大分子的氨基上。通过观察其与抗神经节苷脂 GM(1)抗体或麦胚凝集素（WGA）的特异性相互作用来确认碳水化合物的固定化。通过改变 PAMAM 树枝状大分子的大小或固定在树枝状大分子上的 GlcNAc-C12-NH(2)的浓度，分别制备具有不同 GlcNAc-C12-NH(2)簇大小和密度的表面。分析 GlcNAc-C12-NH(2)固定表面与 WGA 之间的结合表明，PAMAM 树枝状大分子的大小影响 GlcNAc-C12-NH(2)-WGA 相互作用，较大的树枝状大分子导致较高的 WGA 结合常数。
