細菌表面顯示金屬結合胜肽作為對硝基苯胺還原反應之生物催化劑與發展貴重金屬離子的 FRET 生物感測器

Abstract

利用表面顯示技術以源自淋病奈瑟菌 (Neisseria gonorrheaea) 的IgA protease 作為攜帶蛋白，將金屬結合胜肽表現於Escherichia coli和Ralstonia eutropha的外膜上，回收與合成金和鉑奈米粒子。研究結果顯示，膜外表現金屬結合胜肽的細菌不僅能夠還原金和鉑離子，還能將奈米粒子透過金屬結合胜肽表現在細菌表面上。接著我們以吸附金屬奈米粒子的細菌作為生物催化劑，成功地催化對硝基苯胺的還原反應。此外，我們以蛋白質工程的方式設計出對一價銅、一價銀和三價金離子具有選擇性的螢光共振能量轉移蛋白質感測器。以感測蛋白A-66 (CFP-GGSGGS-CueR-GGSGGS-YFP)，進行試管內與活體細胞之金屬離子監測應用。

A surface display system was used for green synthesis of gold and platinum nanoparticles via an autotranspoter protein, immunoglobulin A protease (IgA protease) from Neisseria gonorrheae as carrier proteins. Metal binding peptides were expressed on the outer membranes of Escherichia coli and Ralstonia eutropha to recover metal ions. The results of this study showed that cells expressing metal binding peptides could synthesize and display the nanoparticles on the cell surfaces, simultaneously. Next, the metal nanoparticle-coated microorganisms were used as whole-cell biocatalysts for the reduction of 4-nitroaniline. Besides, we designed a protein-based fluorescence resonance energy transfer (FRET) reporter for detection of copper (I), silver (I), and gold (III) ions. The A-66 reporter (CFP-GGSGGS-CueR-GGSGGS-YFP) was selected for in vitro and in vivo metal ions detection.