Biochemical Services

Protein expression, production and biophysical analysis

We provide Biochemical Services for protein expression, purification, quality control, and interaction studies. These studies often follow computational services related to protein design and engineering. Our Biochemical Services are optimized for high-throughput execution, enabling us to analyze over 400 samples per month, from expression to purification to initial biophysical characterization (stability, activity).

Following high-throughput protein screening, additional experiments can be performed to further characterize each protein sample. Typical characteristics analyzed include stability, activity, oligomeric state, secondary structure, protein-ligand affinity, and binding kinetics. For this, we utilize specialized instruments such as Thermal Shift Assays (TSA), Size-Exclusion Chromatography coupled with Multi-Angle Light Scattering (SEC-MALLS), Bio-Layer Interferometry (BLI), Isothermal Titration Calorimetry (ITC), and Circular Dichroism (CD).

Our expertise in protein research and technology will help you gain key insights into the quality, structure, and function of your proteins. These insights can translate into new perspectives and solutions for various applications, including vaccine development, antibody/protein engineering, biopesticide development, and biosensor development.

Our Biochemical Services

Protein expression

Among the first important data points in a protein construct screening campaign are the expression levels. Plasmids carrying the proteins of interest’s genetic code, are transformed or transfected in a pro- or eukaryotic host, depending on the protein’s expected properties and complexity (e.g. post-translational modifications), followed by expression in or through subcellular compartments of choice. We mainly work with bacterial and mammalian expression systems, but can also work with yeast, insect and plant cell lines. Some expression strategies target intracellular expression while others make use of secretion pathways. Finally, the fraction containing the protein of interest is harvested or extracted from which expression levels can now be determined. A common practical way of achieving this is western blotting whereby the protein mixture is loaded on SDS-PAGE to separate by size followed by specific immunodetection of only the protein of interest. This signal is directly correlated to the capability of expressing the construct in question and serves as a first line of screening and quality control (i.e. protein yield and stability). The outcome of this screening test is a first Go/No-Go decision moment per protein target.

Protein purification

Many applications require not just ample amounts, but also purified recombinant protein. Immobilized Metal Affinity Chromatography (IMAC) is one of the most used first line purification methods exploiting the interaction of a fused poly-histidine (e.g. HHHHHH) tag with cationic metals such a nickel or cobalt. Following the typical binding, washing and elution steps used on chromatographic methods, the purified protein-containing eluates are loaded on SDS-PAGE which can separate proteins based on size. Alternative purification strategies can be used with different protein purification tags or scaffold-based approaches such as antibody fragments or VHHs.

Protein stability

Thermal Stability Assay (TSA) is a widely used technique to probe the thermal stability by determining the temperature at which the protein unfolds. While it is important to note that the absolute value of the measured melting temperature (Tm) is only valid within the confines of the experimental configuration, including the fact that thermal stability does not equal general stability, it does provide a very useful proxy for the protein stability and therefore can serve as a useful experimental screening method. We hereby use a combination of different thermal stability assays to combine the strengths and overcome the limitations of each method.

Protein binding

A protein may be folded, stable and pure, but could still lack its expected binding functionality or structural integrity, especially when significant alterations have been made to alter or improve other characteristics like production yield. We can perform a myriad of protein-protein interaction studies using methods like BLI, ITC, etc.