Formulation: 50 mM HEPES, pH 8.0, with 100 mM sodium chloride, and 10% glycerol
Purity: ≥80% estimated by SDS-PAGE
Formula Weight: 0
Shelf life (days): 365
Notes: Stimulator of interferon genes (STING) is a component of the innate immune response that recognizes and binds to cyclic dinucleotides (CDNs), which either originate from bacteria or are signals of intracellular stress, leading to activation of NF-κB and transcription of immunomodulatory genes, including type I interferon (IFN).{24607,22400,22401,24611,69771} The R232 variant is the most common variant in the human population, found at a frequency of 57.9% in the 1000 Genome Project.{38697} STING is composed of four transmembrane domains at the N-terminus, a helix α1 domain involved in protein dimerization and ligand sensing, and a cytoplasmic C-terminal domain containing the cyclic dinucleotide-binding domain, as well as the TBK1/IRF1-binding site, TBK1 phosphorylation site, and IRF3 docking site.{69772} Various mutations in STING either reduce or increase its activity or binding affinity.{38697,41598,34537,24612} The asparagine-to-alanine substitution at position 242 (N242A) reduces c-di-GMP and 2’3’-cGAMP binding to STING.{35253,24609} Cayman’s STING R232 variant (N242A mutant; human, recombinant) protein can be used for ELISA, enzyme activity assay, and Western blot applications.