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標題: | 類綠螢光蛋白發光團之分子內氫鍵合作效應與螢光淬滅行為之研究 Cooperative Intramolecular Hydrogen Bonding and Fluorescence Quenching Studies of Green Fluorescence Protein-like Chromophores |
作者: | Deng-Hsiang Chang 張登翔 |
指導教授: | 楊吉水(Jye-Shane Yang) |
關鍵字: | 類綠螢光蛋白發光團,分子內氫鍵,合作效應,螢光淬滅, GFP-like chromophores,Intramolecular hydrogen bonding,Cooperative effect,Fluorescence quenching, |
出版年 : | 2014 |
學位: | 碩士 |
摘要: | 氫鍵為一種在自然界中非常重要的非共價鍵結作用力,許多分子因氫鍵的作用而存在著特殊的結構與性質 (如蛋白質或水),甚至可以將氫鍵應用在聚合物或是超分子中。同一個分子可以同時形成數個氫鍵時,在其合作效應的影響下可能使某一氫鍵的鍵能增加或減少。激發態中氫鍵亦扮演重要角色,對於具有氫鍵的發光團分子,合作效應將影響其原有光物理或光化學性質。綠螢光蛋白因其具有高螢光量子產率而成為許多人研究的對象,本實驗室開發出間位胺基取代之綠螢光蛋白發光團m-DMABDI在非質子性溶劑下具有高螢光量子產率,而在質子性溶劑下會因氫鍵的影響導致螢光淬滅。我們曾利用具有分子內氫鍵之1OH以及2OH發光團分子,得知羰基上的氧原子比起亞胺基上的氮原子所形成的氫鍵於激發態淬滅中扮演了較為重要的角色。為了更瞭解這兩個氫鍵對於此發光團的影響,我們更進一步合成出同時具有兩分子內氫鍵之3OH。有別於利用理論計算的方式證明氫鍵在激發態時的合作效應,我們成功地利用實驗的方式發現3OH在乙腈中氫鍵所導致的非輻射放光速率常數 (kHB)為3.41 s-1,比1OH (2.28 s-1)和2OH (0.65 s-1)還要大,甚至大於1OH和2OH的總和 (2.93 s-1),這樣的結果更證明這兩個分子內氫鍵具有合作效應因此加快螢光被淬滅的速率。 Hydrogen bond is an important noncovalent bonding that affects the structures and properties of molecules, polymers, and supramolecules. When there exists multiple hydrogen bonds in a molecule, the cooperative effect could strengthen or weaken the hydrogen bond. Hydrogen bond also plays an important role in photochemical or photophysical properties of chromophores. Green fluorescence protein (GFP) and its analogs are widely used as biological markers, partly because of the high fluorescence quantum yields. We’ve synthesized a highly fluorescent GFP-like chromophore m-DMABDI and found that the fluorescence is readily quenched by the solvent-solute hydrogen bonding in protic solvents. We also synthesized 1OH and 2OH to show that the hydrogen bonding to the carbonyl oxygen plays a more important role than that to the imino nitrogen in deactivating the excited state. To investigate the double hydrogen-bonding effect in this chromophore, we have synthesized 3OH, which has two intramolecular hydrogen bonds, for the studies of the cooperative effect. The results show that the rate constant of nonradiative decay induced by intramolecular hydrogen bonding (kHB) for 3OH is 3.41 s-1, which is larger than 1OH (2.28 s-1), 2OH (0.65 s-1), even the sum of that for 1OH and that for 2OH (2.93 s-1). |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/56169 |
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顯示於系所單位: | 化學系 |
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