Yan Chao, Yersin Alexandre, Afrin Rehana, Sekiguchi Hiroshi, Ikai Atsushi
Laboratory of Biodynamics, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, Midori-ku, Yokohama, Kanagawa 226-8501, Japan.
Biophys Chem. 2009 Sep;144(1-2):72-7. doi: 10.1016/j.bpc.2009.06.009. Epub 2009 Jul 2.
Glycophorin A (GpA) is one of the most abundant transmembrane proteins in human erythrocytes and its interaction with lectins has been studied as model systems for erythrocyte related biological processes. We performed a force measurement study using the force mode of atomic force microscopy (AFM) to investigate the single molecular level biophysical mechanisms involved in GpA-lectin interactions. GpA was mounted on a mica surface or natively presented on the erythrocyte membrane and probed with an AFM tip coated with the monomeric but multivalent Psathyrella velutina lectin (PVL) through covalent crosslinkers. A dynamic force spectroscopy study revealed similar interaction properties in both cases, with the unbinding force centering around 60 pN with a weak loading rate dependence. Hence we identified the presence of one energy barrier in the unbinding process. Force profile analysis showed that more than 70% of GpAs are free of cytoskeletal associations in agreement with previous reports.
血型糖蛋白A（GpA）是人类红细胞中含量最丰富的跨膜蛋白之一，其与凝集素的相互作用已作为红细胞相关生物学过程的模型系统进行了研究。我们使用原子力显微镜（AFM）的力模式进行了一项力测量研究，以研究GpA-凝集素相互作用中涉及的单分子水平生物物理机制。GpA被固定在云母表面或天然存在于红细胞膜上，并用通过共价交联剂包被单体但多价的绒毛小皮伞凝集素（PVL）的AFM探针进行探测。动态力谱研究揭示了两种情况下相似的相互作用特性，解离力集中在60 pN左右，对加载速率的依赖性较弱。因此，我们确定了解离过程中存在一个能量屏障。力谱分析表明，超过70%的GpA没有细胞骨架关联，这与之前的报道一致。
