研究人員在11月在線出版的《自然—化學生物學》期刊上報告說，與試管中的研究相比，一種親眼目睹蛋白質在細胞中摺疊的方法也許能更好地幫助我們深入認識蛋白質的不同功能。
蛋白質是由線性的高分子鏈經過摺疊成三維結構後形成的。蛋白質的功能取決於結構，因此了解這一摺疊過程非常重要。儘管這種摺疊過程在人工實驗環境下已被廣泛研究，但細胞的極複雜的真實環境卻會影響蛋白質的三維結構。
Schepartz和同事將一種接合已知螢光分子的胺基酸標籤打破成兩段，讓它們分別粘貼在分離的蛋白質鏈的兩端。當蛋白質成功摺疊時，這些片段就組合在一起，發出螢光；而當蛋白質不能正常摺疊時，螢光信號就不會出現。（科學時報）
原始出處:
Nature Chemical Biology
Published online: 4 November 2007 | doi:10.1038/nchembio.2007.49
Surveying polypeptide and protein domain conformation and association with FlAsH and ReAsH
Nathan W Luedtke1,3, Rachel J Dexter1, Daniel B Fried1 & Alanna Schepartz1,2
Abstract
Recombinant polypeptides and protein domains containing two cysteine pairs located distal in primary sequence but proximal in the native folded or assembled state are labeled selectively in vitro and in mammalian cells using the profluorescent biarsenical reagents FlAsH-EDT2 and ReAsH-EDT2. This strategy, termed bipartite tetracysteine display, enables the detection of protein-protein interactions and alternative protein conformations in live cells. As proof of principle, we show that the equilibrium stability and fluorescence intensity of polypeptide–biarsenical complexes correlates with the thermodynamic stability of the protein fold or assembly. Destabilized protein variants form less stable and less bright biarsenical complexes, which allows discrimination of live cells expressing folded polypeptide and protein domains from those containing disruptive point mutations. Bipartite tetracysteine display may provide a means to detect early protein misfolding events associated with Alzheimer's disease, Parkinson's disease and cystic fibrosis; it may also enable high-throughput screening of compounds that stabilize discrete protein folds.
Correspondence to: Alanna Schepartz1,2 Email: alanna.schepartz@yale.edu
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