Determination of the Surface Charge Density and Temperature Dependence of Purple Membrane by Electric Force Microscopy

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• 作者：Huiwen Du ; Denghua Li ; Yibing Wang ; Chenxuan Wang ; Dongdong Zhang ; Yan-lian Yang ; Chen Wang
• 刊名：Journal of Physical Chemistry B
• 出版年：2013
• 出版时间：August 29, 2013
• 年：2013
• 卷：117
• 期：34
• 页码：9895-9899
• 全文大小：275K
• 年卷期：v.117,no.34(August 29, 2013)
• ISSN：1520-5207

文摘

We report here the measurement of the temperature-dependent surface charge density of purple membrane (PM) by using electrostatic force microscopy (EFM). The surface charge density was measured to be 3.4 脳 10⁵ e/cm² at room temperature and reaches the minimum at around 52 掳C. The initial decrease of the surface charge density could be attributed to the reduced dipole alignment because of the thermally induced protein mobility in PM. The increase of charge density at higher temperature could be ascribed to the weakened interaction between proteins and the lipids, which leads to the exposure of the charged amino acids. This work could be a benefit to the direct assessment of the structural stability and electric properties of biological membranes at the nanoscale.