ELECTROSTATIC POTENTIALS AND BIOLOGICAL MEMBRANES

长期目标是描述静电和 生物膜的电动性质。 有六 具体目标：（一）调查指控的不确定性 使用多价阳性和阴性膜的效果 以及单价脂质，和冷冻以及流体双层; (ii)为了测量多价脂质（例如， 磷脂酰肌醇4，5-二磷酸，PIP 2）与蛋白质， 在膜溶液附近有几个正电荷 接口（例如，血型糖蛋白、蜂毒肽、视紫红质）;（iii） 确定静电势1 nm从表面的一个 带电膜;（iv）研究静电和 模型膜和生物膜的动电特性 在离细胞膜很远的地方有电荷 溶液界面;（v）研究离子交换性能， PIP 2;（vi）评估静电势在 胞吐作用 已建立的实验技术将用于 测量：平面双层的电导，表面 单分子膜的电势，超声处理的31 P NMR谱 囊泡，囊泡的荧光（来自探针TNS），以及 脂质囊泡和生物膜的电泳迁移率 膜。 将开发一种新的荧光技术; 荧光探针将附着在 神经节苷脂，荧光被阳离子淬灭 Tempamine或铊，以及根据 玻尔兹曼关系 所有这些技术的结果将 与经典理论的预测相比（无论是 古伊-斯托克斯方程），并与现代的预测 统计力学理论是由S.玛西娅，谁会 在这个项目上合作。 实验结果，以及 从这些结果中产生的理论概念是 健康相关，因为PIP 2是两秒的源 细胞中的信使和神经节苷脂参与细胞间的相互作用。 识别. 例如，具有高亲和性的抗体， 神经节苷脂GD 3最近被证明在 黑色素瘤的治疗 关于生物物理学的信息 因此，PIP 2和神经节苷脂的性质应该是感兴趣的， 许多生理学家、生物化学家、细胞生物学家和临床医生。

The long-term objective is to describe the electrostatic and electrokinetic properties of biological membranes. There are six specific aims: (i) to investigate the discreteness-of-charge effect using positive as well as negative membranes, polyvalent as well as monovalent lipids, and frozen as well as fluid bilayers; (ii) to measure the interaction of polyvalent lipids (e.g., phosphatidylinositol 4, 5-bisphosphate, PIP2) with proteins that have several positive charges close to the membrane-solution interface (e.g., glycophorin, melittin, rhodopsin); (iii) to determine the electrostatic potential 1 nm from the surface of a charged membrane; (iv) to investigate the electrostatic and electrokinetic properties of model and biological membranes that have charges a significant distance from the membrane- solution interface; (v) to study the ion exchange properties of PIP2; (vi) to evaluate the role electrostatic potentials play in exocytosis. Established experimental techniques will be used to measure: the conductance of planar bilayers, the surface potential of monolayers, the 31P NMR spectra of sonicated vesicles, the fluorescence (from the probe TNS) of vesicles, and the electrophoretic mobility of both lipid vesicles and biological membranes. A new fluorescence technique will be developed; fluorescent probes will be attached to defined locations on gangliosides, the fluorescence quenched with the cations tempamine or thallium, and the potential estimated from the Boltzmann relation. The results from all these techniques will be compared with the predictions of classical theories (either the Gouy-Stokes equations) and with the predictions of a modern statistical mechanical theory developed by S. Marcelja, who will collaborate on this project. The experimental results, and theoretical concepts that will emerge from these results, are health related because PIP2 is the source of two second messengers in the cell and gangliosides are involved in cell-cell recognition. For example, an antibody with a high affinity for the ganglioside GD3 has recently been shown to be effective in the treatment of melanomas. Information about the biophysical properties of PIP2 and gangliosides should thus be of interest to many physiologists, biochemists, cell biologists and clinicians.