GST Nanoselector Agarose

Description: 

GST Nanoselector Agarose have been specifically designed to bind GST-fusion proteins. GST Nanoselector Agarose is based on small high-affinity recombinant alpaca antibody fragments covalently coupled to the surface of Agarose. GST Nanoselector Agarose is an ideal tool to isolate or purify GST-fusion proteins fast and efficiently.

Ligand: Anti-GST single domain antibody fragment (VHH, Nanobody)
Bead size: ~ 40µm
Reactivity: Recognizes GST or GST fusion protein.
Binding capacity: High binding capacity, 10 µL slurry bind about 20 µg of recombinant GST.
Storage: Shipped at ambient temperature. Upon receipt store at 4°C. Stable for 1 year. Do not freeze.
Storage Buffer: 50 % slurry in PBS containing 20 % Ethanol

Background:

Glutathione S-transferases (GSTs), previously known as ligandins, comprise a family of eukaryotic and prokaryotic phase II metabolic isozymes best known for their ability to catalyze the conjugation of the reduced form of glutathione (GSH) to xenobiotic substrates for the purpose of detoxification. GST can be added to a protein of interest to purify it from solution in a process known as a pull-down assay. This is accomplished by inserting the GST DNA coding sequence next to that which codes for the protein of interest. Thus, after transcription and translation, the GST protein and the protein of interest will be expressed together as a fusion protein. GST Nanoselector Agarose is a ready to use resin for immunoprecipitation/pulldown of GST fusion proteins.

Immunoprecipitation (IP)/Co-IP
Mass spectrometry (MS)
Enzyme activity measurements

Immunoprecipitation protocol

Mammalian cell lysis

Note: Harvesting of cells and cell lysis should be performed with ice-cold buffers. We strongly recommend to add protease inhibitors to the Lysis buffer to prevent degradation of your target protein and its binding partners.

For one immunoprecipitation reaction, we recommend using ~10⁶- 10⁷ cells.

1. Choice of lysis buffer:

* For cytoplasmic proteins, resuspend the cell pellet in 200 µL ice-cold Lysis buffer by pipetting up and down. Supplement Lysis buffer with protease inhibitor cocktail and 1 mM PMSF (not included).

* For nuclear/chromatin proteins, resuspend cell pellet in 200 µL ice-cold RIPA buffer supplemented with DNaseI (f.c. 75-150 Kunitz U/mL), MgCl2 (f.c. 2.5 mM), protease inhibitor cocktail and PMSF(f.c. 1 mM)(not included)

2. Place the tube on ice for 30 min and extensively pipette the suspension every 10 min.

3. Centrifuge cell lysate at 17,000x g for 10 min at +4°C. Transfer cleared lysate (supernatant) to a pre cooled tube and add 300 µL Dilution buffer supplemented with 1 mM PMSF and protease inhibitor cocktail (not included). If required, save 50 µL of diluted lysate for further analysis (input fraction).

Bead equilibration

1. Resuspend the beads by gently pipetting up and down or by inverting the tube. Do not vortex the beads!

2. Transfer 25 µL of bead slurry into a 1.5 mL reaction tube.

3. Add 500 µL ice-cold Dilution buffer.

4. Sediment the beads by centrifugation at 2,500x g for 5 min at +4°C.

5. Discard the supernatant.

Protein binding

1. Add diluted lysate to the equilibrated beads.

2. Rotate end-over-end for 1 hour at +4°C.

Washing

1. Sediment the beads by centrifugation at 2,500x g for 5 min at +4°C.

2. If required, save 50 µL of supernatant for further analysis(flow-through/non-bound fraction).

3. Discard remaining supernatant.

4. Resuspend beads in 500 µL Wash buffer.

5. Sediment the beads by centrifugation at 2,500x g for 5 min at +4°C. Discard the remaining supernatant.

6. Repeat this step at least twice.

7. During the last washing step, transfer the beads to a new tube.

Optional: To increase stringency of the Wash buffer, test various salt concentrations e.g. 150 mM - 500 mM,and/or add a non-ionic detergent e.g. Triton™ X-100.

Elution with 2x SDS-sample buffer

1. Remove the remaining supernatant.

2. Resuspend beads in 80 µL 2x SDS-sample buffer.

3. Boil beads for 5 min at +95°C to dissociate immunocomplexes from beads.

4. Sediment the beads by centrifugation at 2,500x g for 2 min at +4°C.

5. Analyze the supernatant in SDS-PAGE.

Elution with Glycine-elution buffer

1. Remove the remaining supernatant.

2. Add 50–100 µL Glycine-elution buffer and constantly pipette up and down for 30 - 60 sec at +4°C.

3. Sediment the beads by centrifugation at 2,500x g for 5 min at +4°C.

4. Transfer the supernatant to a new tube.

5. Immediately neutralize the eluate fraction with Neutralization buffer.

6. Repeat this step at least once to increase elution efficiency .