- 學位論文
探討高自組裝性之短胜肽序列對膠原蛋白模擬胜肽摺疊和自組裝性質影響
The Effects of High Self-Assembled Oligopeptides on the Folding and Self-Assembly of Collagen Mimetic Peptides
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摘要
膠原蛋白是哺乳動物中含量最多的蛋白質，目前已廣泛用在生醫材料上。為了增加其結構穩定度和應用性，我們設計並製備膠原蛋白模擬胜肽。主要的構想是將具有高自組裝性質的胺基酸序列當成基底，並接上膠原蛋白序列，合成新的膠原蛋白模擬胜肽，目的是利用高自組裝性質的胺基酸序列來幫助原始的膠原蛋白序列形成更穩定且高階的結構，並探討其抑制其它蛋白質聚集的可能性。 研究工作分為兩部分，第一部分是接續研究之前本實驗室所設計和製備的胜肽，這些胜肽是由膠原蛋白序列與貝它類澱粉蛋白序列這兩條序列片段所組成的新胜肽鏈。之前的光譜量測顯示，這些合成的新胜肽中，有一些能夠抑制類澱粉蛋白Ab聚集，有一些在TEM下可以觀察到有別於典型膠原蛋白和類澱粉蛋白這兩種蛋白所形成的纖維。故在第一部分，旨在探討這些胜肽鏈是否對於生物神經細胞會產生毒性，鑑定其是否可以成為新的材料或者是具有潛力的抑制藥物。因這些含Ab序列的膠原蛋白胜肽均具細胞毒性，因此在第二部分，我們選用CILFWG 這段胺基酸序列來做研究，將其接於膠原蛋白相關序列(POG)n之胜肽鏈，共合成五段胜肽: CILFWG、CILFWG(POG)7 、(POG)7CILFWG、OG(POG)4CILFWG和 (POG)7。利用可見光紫外光分光光譜儀、TEM、CD來探討新胜肽鏈的結構特性。 我們由CILFWG(POG)7這段胜肽的實驗結果發現此一具高自組裝性的短序列胜肽除了能夠穩定膠原蛋白摺疊，亦能幫助其自組裝形成大型結構。我們認為CILFWG(POG)7能夠繼續進行其他生物性實驗，來進一步探討其成為新的生物材料之可能性。
並列摘要
Collagen, the most abundant protein in mammals, has been widely used in biomedical materials. In order to increase the structural stability of collagen, we designed and synthesized the collagen mimetic peptides (CMPs) in which an oligopeptide with a high self-assembly propensity was attached. By this design, we expected that the oligopeptide could stabilize the collagen triple helix and assist their self-assembly into higher order structures. Since some of the CMPs containing Ab(16-22) sequence showed the ability to inhibit the aggregation of A protein in our previous studies, in the first part of this study, we further investigated their cytotoxicity by MTT assay. The results indicate that these CMPs are actually toxic to a Neuro cell N2a. Therefore, in the second part, we chose another oligopeptide CILFWG as an attachment to CMPs. From this design, we synthesized a series of CMPs : CILFWG(POG)7 , (POG)7CILFWG, and OG(POG)4CILFWG. The collagen peptide (POG)7 and CILFWG peptide were also synthesized for comparison. We used UV-VIS spectroscopy, TEM, and CD to characterize these peptides. The results showed that the oligopeptide could stabilize the collagen triple helices and assist their self-assembly into higher order structures. In particular, this oligopeptide has a more pronounced effect on CILFWG(POG)7 than any other peptide studied. Thus, this oligopeptide could be potentially useful in designing stable collagen assemblies and related biomaterials.
參考文獻
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