2',5'-oligoadenylate

2',5'-oligoadenylate (2-5A) is a naturally occurring oligonucleotide produced by the interferon-induced enzyme 2',5'-oligoadenylate synthetase (OAS). It is characterized by unique 2',5'-phosphodiester bonds rather than the standard 3',5'-bonds found in most RNA. The molecule serves as a critical second messenger in the innate immune system's antiviral response by binding to and activating Ribonuclease L (RNase L). Once activated, RNase L dimerizes and degrades viral and cellular single-stranded RNA, effectively halting viral replication and protein synthesis. Synthetic analogues of 2-5A, such as Oragen 0004, have been developed to improve stability against phosphodiesterases for potential therapeutic use in treating viral infections (e.g., respiratory syncytial virus, murine hepatitis virus) and metabolic conditions like obesity-related insulin resistance.

Other names

2',5'-linked oligoadenylate2',5'-Appp(A2'p5')nA