S-tag properties and uses:
The S-tag is derived from the N terminus of RNase A. It is a 15 amino acid sequence that is used as an epitope tag and also as a solubility tag. The sequence is: Lys-Glu-Thr-Ala-Ala-Ala-Lys-Phe-Glu-Arg-Gln-His-Met-Asp-Ser. S-tag is suitable for use in many different cell types and has a molecular mass of 42.5 KDa.
Oxford Genetics provides a range of plasmid vectors containing S-tags for use in mammalian, bacterial and yeast cells. We provide S-tags in a range of orientations, to meet all your cloning requirements. Please browse through our products using the ‘Browse Plasmids’ menu. For example we provide S-tags at both N and C sides of the MCS, allowing versatile positioning of your gene, we sell it with and without enzyme cleavage sites (for simple removal of the tag, if required, after protein production), and we sell it in a range of configurations with other tags (such as hexahistidine) to give you maximum flexibility.
Purification of proteins using S-tags: the principle
- A typical S-tag-based purification is as follows:
- Harvest and lyse host cells with expressed S-tagged protein, and clarify by centrifugation
- Pass the lysate slowly through an affinity column containing anti-S-Tag antibodies and wash carefully with buffer.
- Elute the bound S-tagged protein and its binding partner(s) with a buffer containing high levels of free S-Tag peptide
Our product range
Oxford Genetics provides a broad range of plasmids containing N-terminal and C-terminal S tags for mammalian, bacterial and yeast systems. In some plasmids the tags flank reporter genes, while in others they are positioned adjacent the MCS enabling you to insert your own gene in frame as required.
The plasmid structure shown contains an S-Tag positioned downstream of the MCS, to be linked at the C terminal of your gene of interest. The plasmid also contains puromycin resistance driven by the ubiquitin promoter.
Our Plasmid Builder facility also provides a simple means for you to design an efficient strategy for any modifications or cloning manipulations to these plasmids. Finally, as always, although we have designed these plasmids for simple and efficient cloning, we are happy to undertake any cloning steps that you prefer to outsource. You can access all these options through the Plasmid Builder button below.
Simple plasmids containing S-Tag tags: