高等学校化学学报

高等学校化学学报 ›› 2013, Vol. 34 ›› Issue (8): 1894.doi: 10.7503/cjcu20121124

• 有机化学 • 上一篇    下一篇

磷脂和硫酸肝素对αs1-酪蛋白淀粉样纤维沉淀形成的影响

尹建元1, John A. Carver2, David C. Thorn2, 刘继华1   

  1. 1. 吉林大学药学院, 长春 130021;
    2. 阿德莱德大学物理化学学院, 阿德莱德 5005
  • 收稿日期:2012-12-13 出版日期:2013-08-10 发布日期:2013-07-19
  • 通讯作者: 刘继华,女,博士,副教授,主要从事天然产物化学及生物活性研究.E-mail:jljh@sina.com E-mail:jljh@sina.com
  • 基金资助:

    吉林省自然科学基金(批准号: 20130101116JC)资助.

Effects of Lipids and Heparin Sulphate on Formation of Amyloid Fibril from αs1-Casein

YIN Jian-Yuan1, John A. Carver2, David C. Thorn2, LIU Ji-Hua1   

  1. 1. College of Pharmacy, Jilin University, Changchun 130021, China;
    2. School of Physics and Chemistry, Adelaide University, Adelaide 5005, Australia
  • Received:2012-12-13 Online:2013-08-10 Published:2013-07-19

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摘要：

利用ThT荧光分析法、 透射电子显微镜和圆二色光谱检测αs1-酪蛋白形成淀粉样纤维沉淀(Fibril)的动力学过程, 优化了其形成条件, 研究了Fibril形成的影响因素. 实验结果表明, αs1-酪蛋白在65℃高温下, pH=5~5.4的范围内, 加热144 h以上, 可以形成Fibril. 在此过程中, αs1-酪蛋白的二级结构由α螺旋构象向β折叠构象转变. 甘油磷酸胆碱D6PC可以显著地促进αs1-酪蛋白Fibril的形成, 并呈浓度依赖性, 说明一定条件下蛋白质可能与细胞膜的磷脂之间存在相互作用, 从而导致酪蛋白二级构象的转变. 硫酸肝素对αs1-酪蛋白形成Fibril无影响, 说明硫酸肝素对蛋白质二级构象的影响作用因蛋白质的不同而不同, 与不同蛋白质的Fibril形成机制相关.

关键词: αs1-酪蛋白, 淀粉样纤维沉淀, 磷脂, 硫酸肝素, ThT荧光分析法

Abstract:

αs1-Casein is the major protein in milk and has a molecular chaperone action. With the interest in that, whether κ-and αs2-casein can form amyloid fibrils or not, we investigated amyloid fibril formation from αs1-casein by means of ThT assay, transmission electron microscopy and circular dichroism(CD) spectra. The results show that amyloid fibrils formed from αs1-casein at pH=5.0-5.4 and 65℃ under heating for 144 h. The CD spectra show that the structure of αs1-casein has changed from α-helical to β sheet core, which are the special structure characters of fibrils. Lipids of D6PC promoted amyloid fibril formation from αs1-casein in the concentration of 0.3 and 1 mmol/L. Heparin sulphate did not influence the fibril formation from αs1-casein in the test. It is concluded that although αs1-casein has the effects of molecular chaperon, but it could still form fibrils under harsh conditions. Lipids can influence amyloid fibril formation from αs1-casein, depanding on concentration. It suggests that there is relationship between lipid in membrane and amyloid fibril formation. The results are helpful to exploring the mechanism of fibril formation from αs1-casein.

Key words: αs1-Casein, Amyloid fibril, Lipid, Heparin sulphate, ThT assay

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