Naturally-occurring RNA modified nucleoside s2Um for vaccine and cancer research. It exhibits antiviral activity against various viral infections, making it a potential therapeutic option for treating RNA virus-associated diseases. It has been shown to stabilize duplex DNA against thermal denaturation by forming triplexes with complementary sequences. It also stabilizes dsDNA against hydrolysis by the enzyme ribonuclease H (RNase H) and has been used in the design of antisense therapeutics. Thermophilic bacteria use this molecule to synthesize their own thymine nucleotides, which are structurally similar to 2’-O-methyl-2-thiouridine. Its unique properties and versatility make it an essential tool for studying RNA biology and developing antiviral therapies.