不同聚集态下β-乳球蛋白与油酸自组装分子过程构象变化

Conformational changes of self-assembled molecular between different aggregatedβ-Lactoglobulin and oleic acid

采用pH 2、4、6和8环境诱导获得不同聚集态的β-乳球蛋白,并促使其与油酸发生自组装分子过程,采用荧光光谱仪和圆二色谱仪等技术研究不同聚集态β-乳球蛋白在与油酸发生自组装前后的表面疏水性及二三级结构的变化。结果表明,pH 2、4和6环境下诱导的不同聚集态β-乳球蛋白与油酸形成自组装分子后其表面疏水性有所增加,而pH 8环境下获得的解离态β-乳球蛋白油酸自组装分子的表面疏水性发生降低现象;圆二色谱图发现不同pH环境下获得的不同聚集态β-乳球蛋白油酸自组装分子前后其二级结构及组成比例发生不同程度的变化;同步荧光光谱和內源荧光光谱说明pH 2、6和8环境下获得的不同聚集态β-乳球蛋白油酸自组装分子的发色基团周围的三级结构有所变化,而pH 4环境下获得的自组装分子的发色基团周围的三级结构并未改变。

In this study, different aggregated β-lactoglobulins were induced by different pH values,including pH 2,4,6 and 8, which could react with oleic acid to form self-assembled molecular. The surface hydrophobieity, secondary and tertiary structure changes of β-lactoglobulin and self-assembled molecular were determined using fluorescence spectroscopy and circular dichroism （CD） spectroscopy. It was found that the surface hydrophobieity of self-assembled molecular between different aggregated β-lactoglobulin and oleic acid at pH 2,4 and 6 was increased,while that of self-assembled molecular at pH 8 environment was decreased. It can be shown from CD spectroscopy that the content of secondary structure of self-assembled molecular between different aggregated β-lactoglobulin and oleic acid induced by different pH was changed in different degrees. The results of synchronous and intrinsic fluorescence spectroscopy indicated that the tertiary structure around the chromophores in the self-assembled molecular between different aggregated β-lactoglobulin and oleic acid induced by pH Z,6 and 8 was changed,while that of self-assembled molecular at pH 4 was not changed.