Recombinant Human MED21 Protein: Key FAQs & Usage Guide

Recombinant Human MED21 Protein is a recombinant form of the human Mediator complex subunit 21, produced for use in biochemical and cell biology research investigating transcriptional coactivation and Mediator complex assembly.

Product Name

Recombinant Human MED21 Protein

SKU

rp365270

Protein Function

Subunit of the Mediator transcriptional coactivator complex; involved in RNA polymerase II-mediated transcription regulation

Source

Recombinant human protein (expression system to be confirmed with manufacturer)

Recommended Storage

Store at -20°C or -80°C; avoid repeated freeze-thaw cycles (confirm exact conditions on datasheet)

Primary Applications

Biochemical assays, protein-protein interaction studies, Mediator complex research, in vitro transcription studies

What Is MED21 and Why Is It Scientifically Important?

MED21 (Mediator Complex Subunit 21), also known as SURB7 or MED21, is an integral component of the Mediator complex — a large, evolutionarily conserved multi-protein assembly that functions as a transcriptional coactivator for RNA polymerase II (RNAPII)-dependent gene expression. The Mediator complex acts as a molecular bridge between gene-specific transcription factors bound at enhancer or promoter regions and the general transcription machinery assembled at the core promoter.

MED21 is part of the middle module of the Mediator complex and contributes to the structural integrity and functional activity of the complex. Dysregulation of Mediator subunits, including MED21, has been implicated in various disease states, making recombinant MED21 protein a valuable reagent for dissecting transcriptional regulatory mechanisms in both normal physiology and pathological conditions.

Product Specifications and Quality

Aladdin Scientific's Recombinant Human MED21 Protein (SKU: rp365270) is manufactured as a recombinant protein intended for research use. The following points summarize key specification considerations:

• Purity: Recombinant proteins in this category are typically produced to research-grade purity (commonly >85% or >95% by SDS-PAGE); confirm exact purity on the product datasheet.
• Tag Information: Recombinant MED21 may be supplied with an affinity tag (e.g., His-tag) to facilitate purification and downstream detection; verify tag details on the official datasheet.
• Formulation: The protein is typically supplied in a buffered solution; specific buffer composition, concentration, and excipients should be confirmed on the Certificate of Analysis (CoA).
• Endotoxin Level: Endotoxin content, if stated, should be reviewed on the product datasheet for applications sensitive to LPS contamination.

For the most accurate and up-to-date specifications, always refer to the product datasheet and CoA supplied with each lot.

Storage, Handling, and Reconstitution

Proper storage and handling of Recombinant Human MED21 Protein are essential to maintain protein integrity and biological activity:

• Short-term storage: If the protein will be used within 1–2 weeks, storage at 4°C in the supplied formulation buffer is generally acceptable; confirm on the datasheet.
• Long-term storage: For extended storage, aliquot the protein and store at -20°C or -80°C to minimize degradation. Avoid repeated freeze-thaw cycles, as these can reduce protein activity and cause aggregation.
• Reconstitution: If supplied in lyophilized form, reconstitute using the volume of sterile water or buffer specified in the datasheet. Allow the vial to equilibrate to room temperature before opening. Gently mix — do not vortex vigorously.
• Carrier protein: Adding a carrier protein (e.g., 0.1% BSA) to the reconstitution buffer may help stabilize dilute protein solutions.
• Working aliquots: Prepare single-use working aliquots to avoid repeated freeze-thaw cycles.

Research Applications of Recombinant Human MED21 Protein

Recombinant Human MED21 Protein is suitable for a range of biochemical and molecular biology research applications, including but not limited to:

• Protein–protein interaction studies: MED21 can be used in pull-down assays, co-immunoprecipitation experiments, and surface plasmon resonance (SPR) studies to characterize its interactions with other Mediator subunits or transcription factors.
• In vitro binding assays: Use as a binding partner to map interaction domains within the Mediator complex.
• Structural biology: Recombinant MED21 can serve as a component for cryo-EM or X-ray crystallography studies aimed at resolving Mediator complex architecture.
• Enzyme-linked immunosorbent assay (ELISA) standards: Recombinant protein can serve as a positive control or standard curve component in ELISA-based detection assays.
• Antibody validation: Useful as an antigen to validate MED21-specific antibodies by Western blot or dot blot.

All applications should be validated in-house; not all applications may have been tested by the manufacturer for this specific product.

Ordering, Quality Assurance, and Support

Recombinant Human MED21 Protein (SKU: rp365270) is available from Aladdin Scientific. When ordering, consider the following:

• Lot-specific documentation: Each lot is accompanied by a Certificate of Analysis (CoA) detailing purity, concentration, and quality control testing results. Request the CoA before or at the time of purchase.
• Quantity and format: Contact Aladdin Scientific's customer service team to confirm available quantities, formats (e.g., lyophilized vs. liquid), and pricing.
• Technical support: Aladdin Scientific's technical support team can assist with application-specific questions, protocol recommendations, and troubleshooting.
• Returns and replacements: Review Aladdin Scientific's returns and refunds policy prior to ordering. If you receive a damaged or non-conforming product, contact customer service promptly with your order details and the CoA.
• Shipping: Recombinant proteins are typically shipped on dry ice to maintain cold-chain integrity. Confirm shipping conditions and estimated delivery timelines at the time of order.

Frequently asked questions

What is the biological function of MED21 in human cells?

MED21 is a subunit of the Mediator complex, a large multi-protein coactivator that facilitates communication between gene-specific transcription factors and the RNA polymerase II general transcription machinery. It contributes to the structural stability of the Mediator middle module and is essential for regulated transcription of protein-coding genes. Loss or dysregulation of MED21 can impair normal transcriptional programs.

In which expression system is the Recombinant Human MED21 Protein produced?

The specific expression system used to produce Recombinant Human MED21 Protein (rp365270) should be confirmed directly on the product datasheet or by contacting Aladdin Scientific technical support. Common expression systems for recombinant human proteins include E. coli, baculovirus/insect cells, and mammalian cells, each offering different post-translational modification profiles.

How should I store Recombinant Human MED21 Protein to maintain its activity?

For long-term storage, aliquot the protein and store at -20°C or -80°C, avoiding repeated freeze-thaw cycles which can cause protein aggregation and loss of activity. For short-term use (within 1–2 weeks), storage at 4°C is generally acceptable. Always refer to the specific storage recommendations on the product datasheet or CoA for this lot.

What quality controls are performed on Recombinant Human MED21 Protein?

Quality control testing for recombinant proteins typically includes SDS-PAGE for purity assessment, Western blot for identity confirmation, and protein concentration determination. Endotoxin testing may also be performed. The specific QC data for each lot of rp365270 is documented in the Certificate of Analysis; contact Aladdin Scientific to request the CoA for your lot.

Can Recombinant Human MED21 Protein be used for antibody validation?

Yes, recombinant MED21 protein is well-suited for use as a positive control antigen in antibody validation experiments, including Western blot, dot blot, and ELISA. Using the recombinant protein ensures a defined, known-identity antigen to confirm antibody specificity. Ensure the protein tag (if any) does not interfere with the epitope recognized by the antibody being validated.

Is Recombinant Human MED21 Protein suitable for use in in vitro transcription assays?

Recombinant MED21 protein may be used in reconstituted in vitro transcription systems to study Mediator complex function, but suitability depends on the assay format, the presence of appropriate co-factors, and whether the protein retains its native conformation and activity. We recommend contacting Aladdin Scientific technical support to discuss specific experimental requirements before use.

References

1. Allen, B.L. & Taatjes, D.J. (2015). The Mediator complex: a central integrator of transcription. Nature Reviews Molecular Cell Biology, 16(3), 155–166. doi:10.1038/nrm3951
2. Tsai, K.L. et al. (2014). A conserved Mediator-CDK8 kinase module association regulates Mediator-RNA polymerase II interaction. Nature Structural & Molecular Biology, 20(5), 611–619. doi:10.1038/nsmb.2549
3. Aladdin Scientific. Recombinant Human MED21 Protein, SKU rp365270. Product Datasheet.

Products are supplied for research and development use only. Not for use in humans, animals, diagnosis, or therapy.