PEPCF expresses proteins in bacteria, insect and mammalian cells and uses a variety of chromatographic and biophysical techniques for protein purification and characterization.
As the topics investigated by researchers in the life sciences become more and more complex, an interdisciplinary and collaborative approach is often required to successfully address these complicated biological problems. Recombinant proteins are popular tools that are frequently used to investigate many aspects of these biological questions by researchers from different scientific backgrounds. At the EMBL Protein Expression and Purification Core Facility we work together with scientists from various fields, ranging from structural biology to cell biology to medicine and pharmaceutical research. Over the years we have learned that the conditions required for recombinant proteins vary strongly between all of these fields. For example, proteins used for structural biology by a crystallographer or an electron microscopist have different concentration and buffer requirements, and these vary greatly from protein conditions used for in vivo experiments by medical researchers.
Importantly, being unaware of the exact protein requirements for specific types of experiments can negatively influence the outcome of these experiments. Therefore, we are very happy to offer advice on how to perform proper quality control checks to ensure protein samples are correctly folded and active. This will also increase the success rate of downstream experiments in which recombinant proteins are used.
We are very passionate about Protein Quality Control (PQC) as it can influence the success or failure of an experiment. Together with our colleagues from other protein production and biophysical analysis facilities throughout all of Europe, we have established a simple set of PQC guidelines, which are outlined on the P4EU and ARBRE MOBIEU websites.
The majority of the techniques described in these guidelines are readily accessible in most molecular biology laboratories (see table below). To emphasize the importance of PQC, we have also published an opinion piece in Nature Communications and we have outlined the results of a large-scale survey on the effect of PQC on data reproducibility in the European Biophysics Journal.
| Minimum PQC | Technique |
| Purity | SDS-PAGE, mass spectrometry |
| Homogeneity | SEC(-MALS), DLS |
| Identity | Mass spectrometry |
| Extended PQC | Technique |
| Folding state & Conformational stability | Circular dichroism, Nano-DSF, Thermofluor |
| Activity (enzyme) | Activity assay |
| Endotoxin level (in vivo experiments) | LAL assay |
Overall, the usage of biological reagents of poor quality leads to irreproducible and/or failed scientific experiments, thereby also wasting a lot of research money. As proteins are what we love, we think everyone should be able to work with good quality proteins in order to produce reliable and reproducible data. Therefore, we want to spread awareness of the importance of protein quality control and teach researchers of different scientific backgrounds how to easily check if their recombinant proteins fulfil all conditions required for successful downstream applications. As interdisciplinary approaches are becoming the norm in life science research, we imagine this topic will only increase in importance in the future!
If you’re interested in learning more about this topic or use our biophysics services for performing quality control checks on your protein samples, please contact: