MTF-1是一個能調控金屬硫蛋白基因的轉錄因子，它的N端由六個連續的鋅指區域所構成，而C端則包括了三個轉錄活化區域，依序為acidic region、proline-rich region及serine/threonine-rich region。MTF-1的鋅指區域可以感應鋅離子濃度並且結合到特定DNA序列上。在本篇研究中，我們試著純化MTF-1的鋅指區域部分，希望透過鋅指區域蛋白質與表面電漿共振技術的結合，發展出一套專一性用來偵測鋅離子濃度的生物感應系統。我們先利用大腸桿菌系統表現glutathione-S-transferase與鋅指區域的融合蛋白，並且以glutathione beads做初步的純化，接著再以膠體層析管柱進一步分離GST-6ZF與其他蛋白質。把純化過後的GST-6ZF固定在感應片上，接著測試鋅、鈣、鎘、鎳、鈷及鎂等六種金屬離子在不同pH情況下與鋅指感應片的結合情形，發現在pH 4的情況下，鋅指感應片與鋅離子結合的能力優於其他金屬。我們測試了緩衝溶液中各種成份，包括NaCl、Tween-20對金屬與zinc finger感應片之間結合能力的影響，也分析了鋅指感應片對鋅離子的靈敏度，發現即使鋅離子濃度低到1μM，鋅指感應片仍然可以有效偵測。由以上實驗得知，zinc finger感應片在特定的情況下，對鋅離子是有其專一性與靈敏度的。

Metal-responsive transcription factor 1 (MTF-1) is a transcription factor which regulates the gene expression of several metal inducible genes. The N-terminus of MTF-1 is consist of six zinc fingers, and the C-terminus contains three domains associated with transcriptional activation. The zinc finger domains of MTF-1 are able to sense the concentration change of Zn(Ⅱ) and bind to the metal response elements (MREs). In this study, we attempt to purify the zinc finger domains of MTF-1, and try to establish a biomolecule-based biosensor system which is specific for Zn(Ⅱ) detection through the combination of zinc finger protein-conjugated sensor chip and surface plasmon resonance technology. We expressed the glutathione-S-transferase and zinc finger protein fusion protein (GST-6ZF) in E. coli. This fusion protein was initially purified with glutathione beads, followed by gel filtration chromatography. The purified GST-6ZF was immobilized onto a carboxy- methylated dextran matrix (CM5 chip). We evaluted the interaction at different pH values between the zinc finger sensor chip and six metal ions, including Zn(Ⅱ), Ca(Ⅱ), Cd(Ⅱ), Ni(Ⅱ), Co(Ⅱ), and Mg(Ⅱ). It is found that the interaction between zinc finger sensor chip and Zn(Ⅱ) is much stronger than other metal ions at pH 4. The sensitivity of the zinc finger sensor chip to Zn(Ⅱ) is also evaluated. The sensor chip detected the zinc concentration is low as 1μM. Our results show the possibility of using MTF-1 to develop the detection system for bioavailable zinc ions.

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