The specific recognition between a monoclonal antibody (mAb) and its epitope can be used in a tag system that has proved valuable in a wide range of biological applications. Herein, we describe a novel tag called RA-tag that is composed of a seven amino acid sequence (DIDLSRI) and recognized by a highly specific mAb, 47RA, against the bacterial toxin Vibrio vulnificus RtxA1/MARTXVv. By using recombinant proteins with the RA-tag at the N-terminal, C-terminal, or an internal site, we demonstrated that the tag system could be an excellent biological system for both protein purification and protein detection in enzyme-linked immunosorbent, Western blot, flow cytometry, and immunofluorescence staining analyses in Escherichia coli, mammalian cell lines, yeast, and plant. In addition, our RA-tag/47RA mAb combination showed high sensitivity and reliable affinity (KD = 5.90 × 10-8 M) when compared with conventional tags. Overall, our results suggest that the RA-tag system could facilitate the development of a broadly applicable tag system for biological research.

中文翻译：

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来自细菌毒素的新型短肽标签，用途广泛。

单克隆抗体（mAb）及其表位之间的特异性识别可用于已证明在多种生物学应用中有价值的标签系统中。在这里，我们描述了一种称为RA标签的新型标签，该标签由七个氨基酸序列（DIDLSRI）组成，并被抗细菌毒素弧菌RtxA1 / MARTXVv的高度特异性单克隆抗体47RA识别。通过使用在N末端，C末端或内部位点带有RA标签的重组蛋白，我们证明了该标签系统对于酶联免疫吸附剂，蛋白质免疫印迹中的蛋白质纯化和蛋白质检测而言，可能是出色的生物学系统。大肠杆菌，哺乳动物细胞系，酵母和植物中的蛋白质印迹，流式细胞术和免疫荧光染色分析。此外，与传统标签相比，我们的RA标签/ 47RA mAb组合显示出高灵敏度和可靠的亲和力（KD = 5.90×10-8 M）。总体而言，我们的结果表明RA标签系统可以促进生物学研究广泛应用的标签系统的开发。