Meng Guangtao, Chan Judy C K, Rousseau Dérick, Li-Chan Eunice C Y
Faculty of Agriculture, Food Science Building, The University of British Columbia, 6650 N.W. Marine Drive, Vancouver, British Columbia, Canada V6T 1Z4.
J Agric Food Chem. 2005 Feb 23;53(4):845-52. doi: 10.1021/jf040259r.
The interface of 10 or 25% (w/v) bovine serum albumin (BSA), pH 7, buffered solution against mineral or corn oil was studied with a Raman microscope. A gradient of distribution of protein and oil at the interface was observed. The difference spectrum obtained by subtracting the spectrum of mineral or corn oil from that of the BSA/oil interface indicated interactions involving different functional groups of the BSA and the oil molecules. Against mineral oil, the BSA spectrum showed reduced intensity of the tryptophan band at 750 cm(-1) and reduced intensity ratio of the tyrosine doublet at 850-830 cm(-1), indicating changes in the microenvironment of these hydrophobic residues. A negative band at 2850 cm(-1) indicated the involvement of the CH groups in the mineral oil. However, the amide regions, normally assigned to protein secondary structure, were not significantly changed. When the spectrum of BSA was subtracted from the BSA/mineral oil interface spectrum, the resultant difference spectrum showed changes of symmetric and antisymmetric CCC stretches at 980 and 1071 cm(-1), respectively. In contrast, the difference spectrum of BSA/corn oil interface - BSA showed a decrease of CH(2) symmetric stretching at 2850 cm(-1) and a decrease of unsaturated fatty acid hydrocarbon chain stretch at 3010 cm(-1). Raman spectroscopy is a useful tool to study the nature of protein-lipid interactions.
使用拉曼显微镜研究了10%或25%（w/v）牛血清白蛋白（BSA）、pH值为7的缓冲溶液与矿物油或玉米油的界面。观察到界面处蛋白质和油的分布梯度。通过从BSA/油界面的光谱中减去矿物油或玉米油的光谱获得的差示光谱表明，涉及BSA和油分子不同官能团的相互作用。与矿物油相比，BSA光谱显示750 cm⁻¹处色氨酸带的强度降低，850 - 830 cm⁻¹处酪氨酸双峰的强度比降低，表明这些疏水残基的微环境发生了变化。2850 cm⁻¹处的负带表明矿物油中CH基团的参与。然而，通常归因于蛋白质二级结构的酰胺区域没有明显变化。当从BSA/矿物油界面光谱中减去BSA的光谱时，所得差示光谱分别显示980和1071 cm⁻¹处对称和反对称CCC伸缩振动的变化。相比之下，BSA/玉米油界面 - BSA的差示光谱显示2850 cm⁻¹处CH₂对称伸缩振动的降低以及3010 cm⁻¹处不饱和脂肪酸烃链伸缩振动的降低。拉曼光谱是研究蛋白质 - 脂质相互作用性质的有用工具。
