Anlyses of enzymatic reaction about glycoconjugates using Atomic Force Microscopy in single molecule level

原子力显微镜（AFM）可以通过力曲线测量来检测分子间相互作用力。例如，当配体固定在芯片上，受体固定在平板上时，我们可以测量两个分子之间的单分子相互作用力。糖脂微区在生物膜中的分布在纳米尺度上难以观察。利用Verotoxin修饰探针，通过AFM力图谱测量，测定了糖脂Gb 3神经酰胺（Gb 3Cer）在脂质双层中的分布。在本研究中，我们分析了细胞表面o-157的生成物质verotoxin与Gb 3糖分子之间的相互作用力。通过改变加载速率得到了断裂力，并得到了有效键长，这是分析相互作用机理的重要参数。我们检测到了单分子间的相互作用力，并通过对作用力的分析，对相互作用机理进行了更详细的讨论。

Atomic force microscopy (AFM) can detect forces as intermolecular interaction forces by force-curve measurements. For example, when a ligand is immobilized on a chip, and a receptor is immobilized on a plate, we can measure single-molecular interaction forces between two molecules. The distribution of glycolipid microdomain in biomembrane is difficult to observe in nanometer scale. We measured a distribution of glycolipid Gb3Ceramide (Gb3Cer) in lipid bilayer by AFM force mapping measurement using Verotoxin modified tip.In this study, we have analyzed interaction forces between a verotoxin that is a substance responsible for o-157 and Gb3 sugar molecules on a cell surface. The rupture forces were obtained by changing loading rates and we can get an effective bond length which is an important parameter for an analysis of interaction mechanisms. We detected single-molecular interaction forces, and we discussed about the interaction mechanism in more detail by an analysis of the forces.