Coarse-grained simulations on interactions between spectrins and phase-separated lipid bilayers

Spectrin, the principal protein of the cytoskeleton of erythrocyte, plays a crucial role in the stability and flexibility of the plasma membrane of erythrocyte. In this work, we investigate the interactions between spectrins and phase-separated lipid bilayers using coarse-grained molecular dynamics simulation. We focus on the preference of spectrins with different lipids, the effects of the anionic lipids and the residue mutation on the interactions between spectrins and the lipid bilayers. The results indicate that spectrins prefer to contact with phosphatidylethanolamine(PE) lipids rather than with phosphatidylcholine(PC) lipids, and tend to contact with the liquid-disordered(Ld) domains enriched in unsaturated PE.Additionally, the anionic lipids, which show specific interaction with the positively charged or polar amino acids on the surface of the spectrins, can enhance the attraction between the spectrins and lipid domains. The mutation leads to the decrease of the structural stability of spectrins and increases the curvature of the lipid bilayer. This work provides some theoretical insights into understanding the erythrocyte structure and the mechanism of some blood diseases.

基于液体旋光效应的葡萄糖浓度测量

葡萄糖浓度是溶液的主要参量之一。根据葡萄糖溶液的旋光效应,结合电机调制检偏器,通过双光路同步检测,测量两路调制信号的相位差从而得到待测葡萄糖溶液的浓度。实验结果表明:对于浓度范围为0%~50%(质量分数)的葡萄糖溶液,测量最大相对误差约为6.48%。本设计解决了旋光角度测量受机械转动装置限制的问题,测量装置具有结构简单、测量快捷、抗干扰性强等优点。