Dave Anant C, Loveday Simon M, Anema Skelte G, Jameson Geoffrey B, Singh Harjinder
Fonterra Research and Development Centre, Dairy Farm Road, Private Bag 11029, Palmerston North, New Zealand.
J Agric Food Chem. 2014 Apr 9;62(14):3269-3278. doi: 10.1021/jf405441g. Epub 2014 Mar 28.
In this study we investigated the effects of different levels of glucosylation and lactosylation on β-Lg self-assembly into nanofibrils at 80 °C and pH 2. Fibrils in heated samples were detected with the thioflavin T assay and transmission electron microscopy, while SDS-PAGE was used to investigate the composition of the heated solutions and fibrils. Glycation had different effects in the nucleation and growth phases. The effect of glycation on the nucleation phase depended on the degree of glycation but not the sugar type, whereas both the type of sugar and the degree of glycation affected the rate of fibril growth. Glycation by either sugar strongly inhibited self-assembly in the growth phase, and lactosylation produced a much stronger effect than glucosylation. We suggest that the varying glycation susceptibility of different lysine residues can explain these observations. The large, polar sugar residues on the glycated fibrillogenic peptides may inhibit fibril assembly by imposing steric restrictions and disrupting hydrophobic interactions.
在本研究中，我们研究了不同程度的糖基化和乳糖基化对β-乳球蛋白在80℃和pH 2条件下自组装成纳米纤维的影响。通过硫黄素T检测法和透射电子显微镜检测加热样品中的纤维，同时使用SDS-PAGE研究加热溶液和纤维的组成。糖基化在成核和生长阶段有不同的影响。糖基化对成核阶段的影响取决于糖基化程度而非糖的类型，而糖的类型和糖基化程度均会影响纤维生长速率。两种糖的糖基化在生长阶段均强烈抑制自组装，且乳糖基化的作用比糖基化更强。我们认为，不同赖氨酸残基糖基化敏感性的差异可以解释这些观察结果。糖基化的成纤维肽上的大的极性糖残基可能通过施加空间限制和破坏疏水相互作用来抑制纤维组装。
