組成成分與溫度對生物膜彈性性質的影響

Composition and temperature effects on the elastic properties of membranes

邱忠憲(Jhong-Sian Chiu)

指導教授 ： 李明道

國立中央大學/理學院/生物物理研究所/碩士(2015年)

摘要

生物膜在細胞中扮演非常重要的角色，除了保護著細胞，許多由細胞膜媒
介的生物過程也維持細胞的活性，因此研究生物膜成為很重要的課題，近年來
很多學者把生物膜結構以及許多生物過程如胞吞現象、胞吐現象….等等，一一
地解謎，但仍有很多生物過程的原因及機制尚未明瞭，由於不少生物過程都有
透過生物膜的變形來完成，故我們用生物物理的方法來研究生物膜的彈性性
質，希望闡明其原因及機制。
不同細胞的生物膜有不同組成，這些組成和溫度皆對細胞的行為有重要的
影響，我們利用 X 光繞射在不同溫度中測量不同脂質混合物的結構，進一步藉
由改變滲透壓的方法得到其彈性性質，透過了解生物膜的彈性性質，可以更理
解各種重要的生物過程。
實驗結果發現不同的分子形狀會直接影響生物膜的自然曲率半徑，與
DOPE 形狀相同生物分子會使得自然曲率半徑不變，其餘與 DOPE 分子形狀不
同的生物分子會使得自然曲率半徑變大；帶電脂質使得自然曲率半徑也些微的
下降；最後蜂毒胜肽使得 DOPE 的六角型相態極為不易產生；在溫度上升時，
不同的脂質混合物的自然曲率半徑都有了些微的下降。

關鍵字

生物膜 ； 抗菌生態 ； 脂質分子

並列摘要

Biological membranes play very important role for the cell. They not only protect
the cell but also mediate the biological processes to maintain the activity of cell.
Therefore, studying biological membranes is very important. In the past decades, a lot
of membrane structure and membrane-mediated biological processes have been studied.
However, most of the mechanisms of these biological processes are still the puzzles. In
this report, we studied the elastic properties of membranes by biophysical method for
further understanding these processes.
Different types of cells have varied membrane composition of lipids. The lipid
composition and temperature are able to affect the membrane-mediated biological
processes. We used x-ray diffraction to determine the structure of membranes in
different compositions as well as different temperatures. The elastic properties of
membranes were extracted from X-ray data by changing the osmotic pressure. We
should understand the biological processes more through the determination of the
elastic properties of membranes.
Consequently, we found different molecular shapes of the additives compare to
DOPE cause the increase of intrinsic radius of curvature. The negative charged lipids
decrease the intrinsic radius of curvature slightly. Melittin hold DOPE membranes in
the lamellar phase instead of hexagonal phase. Finally, the intrinsic radii of curvature
of all lipid mixtures decrease with temperature increasing.

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