Study of Protein-Lipid Interactions at the Bovine Serum Albumin/Oil Interface by Raman Microspectroscopy

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• 作者：Guangtao Meng ; Judy C. K. Chan ; D&eacute ; rick Rousseau ; and Eunice C. Y. Li-Chan
• 刊名：Journal of Agricultural and Food Chemistry
• 出版年：2005
• 出版时间：February 23, 2005
• 年：2005
• 卷：53
• 期：4
• 页码：845 - 852
• 全文大小：203K
• 年卷期：v.53,no.4(February 23, 2005)
• ISSN：1520-5118

文摘

The interface of 10 or 25% (w/v) bovine serum albumin (BSA), pH 7, buffered solution against mineralor corn oil was studied with a Raman microscope. A gradient of distribution of protein and oil at theinterface was observed. The difference spectrum obtained by subtracting the spectrum of mineral orcorn oil from that of the BSA/oil interface indicated interactions involving different functional groupsof the BSA and the oil molecules. Against mineral oil, the BSA spectrum showed reduced intensityof the tryptophan band at 750 cm^-1 and reduced intensity ratio of the tyrosine doublet at 850-830cm^-1, indicating changes in the microenvironment of these hydrophobic residues. A negative bandat 2850 cm^-1 indicated the involvement of the CH groups in the mineral oil. However, the amideregions, normally assigned to protein secondary structure, were not significantly changed. When thespectrum of BSA was subtracted from the BSA/mineral oil interface spectrum, the resultant differencespectrum 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 decreaseof CH₂ symmetric stretching at 2850 cm^-1 and a decrease of unsaturated fatty acid hydrocarbonchain stretch at 3010 cm^-1. Raman spectroscopy is a useful tool to study the nature of protein-lipidinteractions.Keywords: Raman microspectroscopy; protein; lipid; interface; bovine serum albumin