Moorepark Food Research Centre, Teagasc, Moorepark, Fermoy, County Cork, Ireland.
J Agric Food Chem. 2010 Mar 24;58(6):3667-73. doi: 10.1021/jf9042908.
The aggregation process of beta-lactoglobulin (beta-lg) from 0 min to 20 h was studied using atomic force microscopy (AFM), scanning transmission electron microscopy (STEM), sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), and in situ attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR). Fibril assembly was monitored in real time using AFM up to 20 h. From 0 to 85 min, beta-lg monomers deformed and expanded with some aggregation. After 85 min, fibrillar structures were formed, exceeding 10 mum in length. Fibrillar structures were confirmed by STEM. Secondary structural changes occurring during fibril formation were monitored by ATR-FTIR at 80 degrees C and indicated a decrease in alpha-helix content and an increase in beta-sheet content. SDS-PAGE indicated that fibrils were composed of polypeptides and not intact monomers. In this study, beta-lg and whey protein isolate (WPI)-derived fibrils, including some double helices, in water were observed by AFM under ambient conditions and in their native aqueous environment.
使用原子力显微镜（AFM）、扫描透射电子显微镜（STEM）、十二烷基硫酸钠-聚丙烯酰胺凝胶电泳（SDS-PAGE）和原位衰减全反射傅里叶变换红外光谱（ATR-FTIR）研究了β-乳球蛋白（β-lg）从 0 分钟到 20 小时的聚集过程。使用 AFM 实时监测纤丝组装，最长可达 20 小时。从 0 到 85 分钟，β-lg 单体发生变形和膨胀，发生了一些聚集。85 分钟后，形成了纤维状结构，长度超过 10μm。STEM 证实了纤维状结构的存在。ATR-FTIR 在 80°C 下监测到纤维形成过程中发生的二级结构变化，表明α-螺旋含量减少，β-折叠含量增加。SDS-PAGE 表明纤维由多肽组成，而不是完整的单体。在这项研究中，在环境条件下和其天然水相环境中，使用 AFM 在水中观察到了β-lg 和乳清蛋白分离物（WPI）衍生的纤维，包括一些双链。
