蛋白質如何摺疊? 科學家仍無法解釋蛋白質是如何摺疊成其最終構造的。 蛋白質是藉由無數構形的改變來形成專一立體結構，為了解蛋白質摺疊的本質， 我們必須有系統地探討早期摺疊過程。 在本計畫中，我們以一個以光驅動的包覆策略，從奈秒時間範圍開始，偵測蛋白質摺疊的整個過程，我們的標的蛋白質是一種抗凍蛋白RD1，利用其蛋白質中心有一個小洞的性質，藉定點突變法改變小洞周圍第七個胺基酸Ala至Cys (命名為RD1-A7C)，在Cys上加一個對光不穩定的包覆物，由於包覆物疏水性的推斥作用而阻撓蛋白質摺疊，再用極短的雷射光打斷此對光不穩定的包覆物，而啟動蛋白質摺疊成其自然構造。
於此論文中，我們合成一個對光不穩定的包覆化合物4-hydroxyphenacyl bromide (HPB)，並大量表現及純化RD1-A7C。 接著，HPB被成功地加到RD1-A7C上 (命名為RD1-A7C-HP)。 最後，我們研究了RD1-A7C-HP的光解、 結構特性、和其折疊動力學。

How do proteins fold? Scientists still can’t find a rule to explain how it works. Proteins organize themselves into specific three-dimensional structures through the myriads of conformational changes. In order to understand the intrinsic principle of protein folding, early events of folding process have to be systematically explored. Here we proposed a photo-triggered caging-strategy to analyze the whole folding process of a protein on a nanosecond time-scale. Our target protein is an antifreeze protein, RD1, taking advantage of the existence of a small cavity in the center of the protein. We change Ala-7 of RD1 to Cys (designated RD1-A7C) by site-directed mutagenesis and add a photolabile cage group to the residue Cys around the cavity. The bulky size of the cage can hinder the hydrophobic packing and unfold the protein. A short laser pulse is used to break the photolabile cage and to initiate the refolding of the protein toward its native state.
In this work, we synthesized the photolabile cage compound 4-hydroxyphenacyl bromide (HPB). The protein RD1-A7C was expressed and purified. HPB was successfully added to the RD1-A7C protein (denoted RD1-A7C-HP). Finally, the photolysis, structural characterization, and folding kinetics of RD1-A7C-HP were studied.

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