流行性感冒病毒時時對全球生命造成的威脅不容小覷，本文聚焦於流感病毒
表面的膜蛋白分子：血球凝集素2 (hemagglutinin2，HA2)，尤其是其膜外區域
(ectodomain)。針對膜外區域與膜的直接交互作用之探討，以及作為未來可能的
摺合與結構轉換之動力學實驗的基礎數據，本文以數種物理化學方法，嘗試對於
HA2 膜外區域的若干特性進行分析與探討。
首先筆者以衰減全反射紅外線光譜 (ATR-FTIR)、圓二色極譜 (CD)以調查HA2
膜外區域對膜的擾動及其二級結構，我們發現其具有高度α螺旋比例但對膜的本
身並無顯著擾動。接著，作為後續動力學實驗的基礎，筆者利用圓二色極譜數據
加上不同的螢光 (Rhodamine螢光標定，以及樣本本身的色胺酸螢光)作為工具，
觀察蛋白樣本在不同環境下對於變性劑的反應，並找出結構從有到無之間的臨界
點。
除此之外，本文以三種不同的摺合路徑處理樣本並進行實驗以相互比較，各
個路徑樣本雖然大致相同，然而其中表現出許多差異，值得討論比較。另外，筆
者以膠體電泳配合化學聯結劑 (chemical crosslinker)進行了蛋白樣本形成多聚體傾向的一系列調查，發現這段膜外區域蛋白是以單體為主，且形成多聚體的
傾向並不高；多聚體中傾向較高者為雙體及其倍數體，鮮有單純的三聚體存在。
本論文的結果有助於日後摺合動力學實驗的進行以及改善蛋白樣本的製備流程。此外，對於HA2 膜外區域的特性也產生若干推論，增進吾人對其認識與了解。

The influenza virus have become a global threat for years. In this research, we put the focus on the influenza virus membrane protein hemagglutinin2 (HA2) ectodomain region. Several means and experiment have been executed in order to understand more about the protein, including attenuated total reflection infrared spectroscopy (ATR-FTIR), circular
dichorism (CD), several guanidine (denaturant) titration equilibrium experiments: on CD spectra, on UV spectra of rhodamine (fluorescence emitting group) labeled protein samples, and on the emission spectra of
tryptophan on the protein sample strand. And additionally, the gel electrophoresis experiment.
After the investigation and experiment around the protein sample, the nature of HA2 ectodomain, such as membrane interaction, protein structure,
difference under acidic and neutral buffers, and oligomer-formation
tendency, become more concrete, with little new inferences.
The research gives us a more clear picture of the hemagglutinin protein
ectodomain area. Furthermore, by the guanidine titration data mentioned
above, we are able to accomplish the further works such as the folding
kinetic experiment in the near future.

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