Investigating the possibility of using the Fa5/8C-like domain of Paenibacillus LamA as a tag to increase the protein expression and purification efficiency

• Main Authors: Chun-Wei Chang, 張鈞維
• Other Authors: 孟孟孝
• Format: Others
• Language: zh-TW
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/37137559628125822782

碩士 === 國立中興大學 === 生物科技學研究所 === 100 === Protein fusion tags could be applied in several biological techniques, such as protein affinity purification and expression and immunoblotting. The familiar fusion tags include His tag, maltose binding protein and FLAG tag. The Fa5/8C like domain, or called discoidin-like domain, of the Paenibacillus β-1,3 glucanase LamA is able to bind to various carbohydrates including chitin, lichenan and avicel. In this study, we discover that the solubility of Fa5/8C like domain could be affected by different pH environment. This study aimed to investigate the possibility of using the Fa5/8C to develop as a new protein purification process without chromatography procedure. To test this idea, I fused the Fa5/8C-like domain at the N-terminus of green fluorescence protein, a bacterial laccase, human 6-phosphoglucose isomerase (hPGI) and matrix metalloproteinase-1 (MMP-1). The results indicate that the N-terminal Fa5/8C like domain could enhance the expression of GFP, laccase, hPGI and MMP-1, but decrease its activity when GFP fused with Fa5/8C like domain. The solubility in different pH of the fusion proteins was tested, and the result showed that the fusion proteins could be precipitated at pH 6.0 and be resolved at pH 8.0. The study demonstrated that this bacterial Fa5/8C like domain has potential as an protein tag to increase the protein expression and purification efficiency; however, the detail operation conditions remain to be analyzed.