流体脂质双层膜的红外光谱学。
Infrared spectroscopy of fluid lipid bilayers.
作者信息
Hull Marshall C, Cambrea Lee R, Hovis Jennifer S
机构信息
Department of Chemistry, Purdue University, West Lafayette, Indiana 47907-2018, USA.
出版信息
Anal Chem. 2005 Sep 15;77(18):6096-9. doi: 10.1021/ac050990c.
Infrared spectroscopy is a powerful technique for examining lipid bilayers; however, it says little about the fluidity of the bilayer-a key physical aspect. It is shown here that it is possible to both acquire spectroscopic data of supported lipid bilayer samples and make measurements of the membrane fluidity. Attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FT-IR) is used to obtain the spectroscopic information and fluorescence recovery after photobleaching (FRAP) is used to determine the fluidity of the samples. In the infrared spectra of lipid bilayers composed of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine, the following major peaks were observed; nu(as)(CH3) 2954 cm(-1), nu(s)(CH3) 2870 cm(-1), nu(as)(CH2) 2924 cm(-1), nu(s)(CH2) 2852 cm(-1), nu(C=O) 1734 cm(-1), delta(CH2) 1463-1473 cm(-1), nu(as)(PO2-) 1226 cm(-1), nu(s)(PO2-) 1084 cm(-1), and nu(as)(N+(CH3)3) 973 cm(-1). The diffusion coefficient of the same lipid bilayer was measured to be 3.5 +/- 0.5 micom(2)/s with visual recovery also noted through use of epifluorescence microscopy. FRAP and visual data confirm the formation of a uniform, mobile supported lipid bilayer. The combination of ATR-FT-IR and FRAP provides complementary data giving a more complete picture of fully hydrated model membrane systems.
红外光谱法是研究脂质双层的一种强大技术；然而，它对双层的流动性这一关键物理方面却几乎没有涉及。本文表明，既可以获取支撑脂质双层样品的光谱数据，又能够测量膜的流动性。采用衰减全反射 - 傅里叶变换红外光谱法（ATR - FT - IR）获取光谱信息，并用光漂白后荧光恢复法（FRAP）测定样品的流动性。在由1 - 棕榈酰 - 2 - 油酰 - sn - 甘油 - 3 - 磷酸胆碱组成的脂质双层的红外光谱中，观察到以下主要峰：不对称甲基伸缩振动（ν(as)(CH3)）2954 cm⁻¹、对称甲基伸缩振动（ν(s)(CH3)）2870 cm⁻¹、不对称亚甲基伸缩振动（ν(as)(CH2)）2924 cm⁻¹、对称亚甲基伸缩振动（ν(s)(CH2)）2852 cm⁻¹、羰基伸缩振动（ν(C = O)）1734 cm⁻¹、亚甲基弯曲振动（δ(CH2)）1463 - 1473 cm⁻¹、不对称磷酸根伸缩振动（ν(as)(PO₂⁻)）1226 cm⁻¹、对称磷酸根伸缩振动（ν(s)(PO₂⁻)）1084 cm⁻¹以及不对称三甲铵离子伸缩振动（ν(as)(N⁺(CH3)3)）973 cm⁻¹。通过落射荧光显微镜观察到相同脂质双层的扩散系数经测量为3.5 ± 0.5 μm²/s，且有明显的荧光恢复。FRAP和视觉数据证实形成了均匀、可移动的支撑脂质双层。ATR - FT - IR和FRAP的结合提供了互补数据，能更全面地描绘完全水合的模型膜系统。
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