Using the Cherry tag vectors, recombinant protein expression is first detectable from the color of the bacterial pellet: the bacteria expressing a soluble fused protein are red. As lack of solubility is a major problem when expressing recombinant protein in E. coli, the Cherry tag system is convenient for rapid screening and optimization of protein solubility. The tag itself being highly soluble, it can increase the solubility of the target protein.

Furthermore, it is easy to visualize binding of the protein to the column (affinity or ion exchange) and to verify the absence of remaining protein of interest in the effluent. During elution, it is not necessary to collect multiple fractions and to analyse it to localize the target protein. Indeed, the Cherry tag system allows you to collect only the fraction containing the protein of interest.  

When using the Cherry tag system, it is possible to quantify the protein concentration at any step (from protein production to the end of purification): a simple absorbance measurement at 413nm allows specific and accurate calculation of the target protein concentration.

Kit Content

The Cherry tag was inserted in the StabyExpress^TM T7  vector to yield CherryExpress kit combining multiple advantages: T7 expression, plasmid stabilization and protein visualization. Different types of Cherry^TMExpress kits are available: cherry tag as N-terminal (pSCherry1 plamsid) or C-terminal tag (pSCherry3 plasmid), kit containing either electrocompetent cells or chemically-competent cells. All kits contain DNA of the vector (pSCherry1 or pSCherry3), DNA of the pStaby1.2 vector, chemically- or electro- competent bacteria for cloning (CYS21) and expression (SE1), regeneration medium, sequencing primers, and the instruction manual. Additional CYS21 or SE1 competent bacteria can be purchased separately.

pScherry 1 vector for Cherry N-terminal tag

pSCherry3 vector for Cherry C-terminal tag

Benefits of the Cherry^TM Tag system

• Direct visualization of the protein of interest;
• No need of any special apparatus or reagents;
• Rapid screening and optimization of protein expression and solubility;
• Easy quantification of the protein of interest;
• High yield of protein production using Staby^TM systems with or without antibiotics