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SUMO-tagged Proteins

Small Ubiquitin-like Modifiers, also as known as SUMO proteins, are a protein family composed of various small proteins to modify function of other proteins. SUMO can be covalently attached to other proteins and detached from them in cells, participating in various cellular processes include signal transduction, nuclear transport, and protein stabilization. After covalent attachment to cellular targets, SUMO mediates protein-DNA and protein-protein interactions, and regulates localization, solubility, and stability of the target protein.

SUMO-tagged protein expression system
Fusion Tag: SUMO tag.
Purification Method: Ion affinity chromatography.
Tag Removal: SUMO protease.
Products: Purified recombinant proteins.
Quality Characterization: SDS-PAGE.
Typical Timeline: 8-12 weeks.

1. SUMO fusion tag can be fused to target proteins conveniently and directly.
2. Expression level and solubility of recombinant SUMO-tagged proteins can be dramatically enhanced.
3. Easy removal of the SUMO fusion tag based onion affinity chromatography with nickel-chelating resin.
4. Allow production of native proteins with desired N-terminus (not for proline) using SUMO Protease.
5. SUMO Protease do not cleave the fused protein of interest.

SUMO protease
SUMO protease is highly specific to recognize the tertiary structure of SUMO fusion tag, and perform unique and precise cleavage at the C-terminus of the SUMO fusion tag. Compared with other proteases for GST tag or MBP tag cleavage, SUMO protease do not deliver non-specific cleavage. Since the SUMO protease contains a N-terminal His tag as well as the SUMO tag in recombinant proteins, they both can be easily removed to only leave the target protein. SUMO protease shows high activity in a wide variety of buffer conditions such as pH and detergent concentration, allowing flexibility in cleavage protocols.

SUMO-tagged proteins cleavage guidelines
1. Perform the cleavage with partially or fully purified SUMO-tagged proteins.
2. SUMO protease optimally works in a reaction buffer containing approximately 150 mM NaCl in most cases, varying from 100 mM to 300 mM.
3. Imidazole concentration should be kept below 150 mM in case of adverse effect on the activity of the SUMO protease.

Troubleshooting for SUMO-tagged proteins cleavage

Problem Reason Solution
No target protein detection Check the wrong fraction Check the flow-through rather than eluted fraction for your target protein
Large amount of uncleaved SUMO-tagged protein Recombinant protein denatured Perform your recombinant protein purification under native conditions
Cysteine protease inhibitor presents in purification Make sure there is no cysteine protease inhibitors
DTT oxidization occurs in SUMO protease buffer  Prepare fresh DTT, and add to a final concentration of 1 mM
High imidazole concentration Imidazole concentration should be no more than 150 mM in the cleavage reaction
Dialyze eluted fractions of  target protein, reducing the imidazole concentration
High salt concentration NaCl concentration should be around 150 mM in the cleavage reaction
Dialyze eluted fractions of  target protein, reducing the salt concentration
Protein with a starting proline, lysine, valine, or leucine Add a serine to the N-terminus of target protein to allow SUMO-tagged protein cleavage

Creative Biostructure is rich-experienced in SUMO-tagged protein expression and purification, and we have established a resourceful technical support platform in order to help your custom project. Please see the related services for more information and feel free to Contact Us.