CHEMBL5736652

Surface Plasmon Resonance (SPR) Binding: Surface plasmon resonance (SPR) STING agonist binding studies were carried out using a Biacore T200 instrument (GE Healthcare) at 4° C. in a 150 mM KCl, 25 mM Hepes (pH 7.5), 1 mM TCEP, 2.5 mM MgCl2, 5% (v/v) glycerol, 0.005% (v/v) P20, 1% (v/v) DMSO running buffer. The recombinant protein immobilized on the streptavidin chip was either human WT or H232R STING. A truncated construct of STING was used in all studies. The STING constructs were comprised of residues 155-341 with both N- and C-terminal truncations; the N-terminal transmembrane domains were removed (1-154), as well as the C-terminal tail (342-379). A highly specific N-terminal biotinylation was achieved enzymatically with the E. coli biotin ligase (BirA) and inclusion of the high-affinity biotinylation peptide AviTag™. A Carboxymethylated dextran pre-immobilized with streptavidin (series S Streptavidin CM5 Sensor Chip) was used to capture the biotinylated STING protein. Test compound injections were made at a flow rate of 100 μl per minute with a 60 second association time and variable dissociation time. A three-fold dilution series from a 10 μM starting concentration was used for all test compounds. Data analysis was performed using the BiacoreT200 data evaluation software package (GE Healthcare).