High Quality Protein Supply

Domainex’s highly experienced Protein Sciences team can generate crystallography-grade proteins in multi-mg quantities using E. coli and Baculovirus-infected insect cell expression systems.

Our scientists can utilize standard bioinformatics/literature-informed approaches or Domainex’s proprietary technology, Combinatorial Domain Hunting (CDH).

Case Study: CD73

CD73 (also known as ecto-50-nucleotidase, e5NT) is a eukaryotic extracellular glycoprotein with potential applications in the treatment of cancer and inflammation. CD73 catalyses the hydrolysis of extracellular AMP to adenosine and plays a pivotal role in switching on adenosine signalling via the P1 receptors of the purinergic signalling pathway.

Domainex was tasked with establishing a CD73 biochemical assay and a ligand binding assay using Microscale Thermophoresis (MST) as part of a small molecule drug discovery programme. Commercially available CD73 was found to be of insufficient quality for the MST studies, so Domainex was also tasked with producing high quality CD73 protein to support these assays.

Recombinant CD73 was successfully isolated from E.coli inclusion bodies, refolded and purified to homogeneity in multi-milligram quantities. The resulting protein was not only used to screen the output from a LeadBuilder Virtual screen by both biochemical and MST assays, but was of sufficiently high yield and quality to enable additional in-house STD-NMR and X-ray crystallography studies.

Figure 1: X-ray crystal structure of CD73 bound to adenosine 5′-(α,β-methylene)diphosphate (AMPCP) a CD73 inhibitor (dataset resolution 1.7Å). The structure overlays well with the Apo open conformation structure which was also solved.