A novel multi-affinity tag system to produce high levels of soluble and biotinylated proteins in Escherichia coli

• Published in: Protein expression and purification Vol. 33; no. 2; pp. 238 - 245
• Main Authors: Ashraf, S.Salman, Benson, R.Edward, Payne, E.Sturgis, Halbleib, Cale M, Grøn, Hanne
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.02.2004
• Subjects: AviTag; Base Sequence; Biotinylation; Carrier Proteins - genetics; Carrier Proteins - metabolism; Culture Media; DNA Gyrase - chemistry; DNA Gyrase - genetics; DNA Gyrase - metabolism; E. coli; Ef-Tu; Escherichia coli - genetics; Escherichia coli Proteins - biosynthesis; Escherichia coli Proteins - chemistry; Escherichia coli Proteins - isolation & purification; Fusion proteins; Genetic Vectors; Glucocorticoid receptor; GyrA; His-tag; Histidine - chemistry; Humans; In vivo biotinylation; Maltose binding protein; Maltose-Binding Proteins; Models, Biological; Molecular Sequence Data; Peptide Elongation Factor Tu - chemistry; Peptide Elongation Factor Tu - genetics; Peptide Elongation Factor Tu - metabolism; Plasmids; Protein solubility; Receptors, Cytoplasmic and Nuclear - genetics; Receptors, Cytoplasmic and Nuclear - metabolism; Receptors, Glucocorticoid - genetics; Receptors, Glucocorticoid - metabolism; Recombinant Fusion Proteins - biosynthesis; Recombinant Fusion Proteins - chemistry; Recombinant Fusion Proteins - isolation & purification; Recombinant protein expression; Solubility; TufB; In vivo biotinylation; GyrA; Ef-Tu; His-tag; Glucocorticoid receptor; TufB; Protein solubility; AviTag; Fusion proteins; E. coli; Maltose binding protein; Recombinant protein expression
• ISSN: 1046-5928; 1096-0279
• DOI: 10.1016/j.pep.2003.10.016

We describe here a novel multi-affinity tag vector that can be used to produce high levels of soluble, in vivo biotinylated proteins in Escherichia coli. This system combines the solubility-enhancing ability of maltose-binding protein (MBP), the versatility of the hexahistidine tag (His 6), and the site-specific in vivo biotinylation of a 15-amino acid tag (AviTag). We used this multi-tag system in an attempt to improve expression levels of two prokaryotic proteins—elongation factor Tu (TufB) and DNA gyrase subunit A (GyrA)—as well as two eukaryotic nuclear receptors—glucocorticoid receptor (GR) and small heterodimer partner (SHP). The multi-tag system not only vastly improved the expression of the two prokaryotic proteins tested, but also yielded complete, site-specific, in vivo biotinylation of these proteins. The results obtained from the TufB expression and purification are presented and discussed in detail. The nuclear receptors, though soluble as fusion partners, failed to remain soluble once the MBP tag was cleaved. Despite this limitation of the system, the multi-affinity tag approach is a useful system that can improve expression of some otherwise insoluble or poorly expressing proteins, to obtain homogeneous, purified, fully biotinylated protein for downstream applications.