2'2'-cgamp

2'2'-cGAMP is a synthetic dinucleotide (CDN) that contains non-canonical 2'5'-phosphodiester bonds. It binds to the adapter protein stimulator of interferon genes , which is a component of the innate immune response that activates the type I interferon pathway when bound to cyclic dinucleotides. 2'2-cGAMP shows weaker binding to STING than 2'3'-cGAMP but binds more strongly than 3'3'-cGAMP , cyclic di-GMP , or 3'2'-cGAMP, which bind in the micromolar range (Kds = 1.04, 1.21, or 1.61 μM, respectively). Despite weaker binding, 2'2'-cGAMP induces IFN-β production in the same concentration range as 2'3'-cGAMP (EC50s = 15.8 and 19.4 nM, respectively, in L929 cells).

2',3'-cGAMP sodium (2'-3'-cyclic GMP-AMP sodium) is a second messenger in cellular innate immunity, catalyzed by cGAMP synthase (cGAS) under DNA binding conditions. It binds to STING to form a dimer, inducing the production and expression of interferon-β and other cytokines.

2',3'-cGAMP-C2-PPA (45) is a cyclic di-nucleotide that acts as a STING agonist (US20210015941A1). It is a drug-linker conjugate for antibody-drug conjugates (ADC) used in the targeted treatment of cancer.

3'3'-cGAMP is a second messenger produced in bacteria by specific dinucleotide cyclases. It contains canonical 3'5'-phosphodiester bonds and regulates chemotaxis, colonization, and other cellular functions. 3'3'-cGAMP shows weaker binding to the adapter protein stimulator of interferon genes (STING; Kd = 1.04 μM) than 2'2'-cGAMP and 2'3'-cGAMP but has similar binding affinity to 3'2'-cGAMP (Kd = 1.61 μM) and cyclic di-GMP . 3'3'-cGAMP induces IFN-β mRNA expression in L929 cells (EC50 = 40.5 nM).