通过厚度剪切模式谐振器和计算机模拟对膜联蛋白A1介导的膜-膜相互作用进行研究。

Scrutiny of annexin A1 mediated membrane-membrane interaction by means of a thickness shear mode resonator and computer simulations.

作者信息

Kastl Katja, Herrig Alexander, Lüthgens Eike, Janshoff Andreas, Steinem Claudia

机构信息

Institut für Analytische Chemie, Chemo- und Biosensorik, Universität Regensburg, 93040 Regensburg, Germany.

出版信息

Langmuir. 2004 Aug 17;20(17):7246-53. doi: 10.1021/la0495332.

Abstract

The dissipational quartz crystal microbalance (D-QCM) technology was applied to monitor the adsorption of vesicles to membrane-bound annexin A1 by simultaneously reading out the shifts in resonance frequency and dissipation. Solid-supported membranes (SSMs) composed of a chemisorbed octanethiol monolayer and a physisorbed 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine/1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoserine monolayer were immobilized on the gold electrode of a 5 MHz quartz plate. Adsorption and desorption of annexin A1 to the SSM was followed by means of the QCM technique. After nonbound annexin A1 was removed from solution, the second membrane binding was monitored by the D-QCM technique, which allowed distinguishing between adsorbed and ruptured vesicles. The results show that vesicles stay always intact independent of the amount of bound annexin and the vesicle and buffer composition. It was shown that the vesicle adsorption process to membrane-bound annexin A1 is fully irreversible and is mediated by two-dimensional annexin clusters. For N-terminally truncated annexin A1, a decrease in the amount of bound vesicles was observed, which might be the result of fewer binding sites presented by the annexin A1 core. Supported by computer simulations, the results demonstrate that the vesicle adsorption process is electrostatically driven, but compared to those of sole electrostatic binding, the rate constants of adsorption are 1-2 orders of magnitude smaller, indicating the presence of a potential barrier.

摘要

耗散型石英晶体微天平(D-QCM)技术通过同时读出共振频率和耗散的变化,用于监测囊泡与膜结合膜联蛋白A1的吸附。由化学吸附的辛烷硫醇单层和物理吸附的1-棕榈酰-2-油酰-sn-甘油-3-磷酸胆碱/1-棕榈酰-2-油酰-sn-甘油-3-磷酸丝氨酸单层组成的固体支撑膜(SSM)固定在5 MHz石英板的金电极上。通过QCM技术跟踪膜联蛋白A1在SSM上的吸附和解吸。从溶液中去除未结合的膜联蛋白A1后,通过D-QCM技术监测第二次膜结合,该技术能够区分吸附的囊泡和破裂的囊泡。结果表明,囊泡始终保持完整,与结合的膜联蛋白的量以及囊泡和缓冲液组成无关。结果表明,囊泡对膜结合膜联蛋白A1的吸附过程是完全不可逆的,并且由二维膜联蛋白簇介导。对于N端截短的膜联蛋白A1,观察到结合的囊泡数量减少,这可能是膜联蛋白A1核心呈现的结合位点较少的结果。在计算机模拟的支持下,结果表明囊泡吸附过程是由静电驱动的,但与单独的静电结合相比,吸附速率常数小1-2个数量级,表明存在潜在的屏障。

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