SARS-CoV-2 2'-O-methyltransferase (nsp16) (nsp16)

SARS-CoV-2 2'-O-methyltransferase, commonly known as nsp16, is a viral enzyme that plays a pivotal role in the maturation of viral messenger RNA (mRNA). It functions as part of a heterodimeric complex with nsp10, which acts as a necessary cofactor to stabilize the nsp16 catalytic site and facilitate S-adenosyl-L-methionine (SAM) binding [1][2]. The primary biological function of nsp16 is to catalyze the transfer of a methyl group from SAM to the 2'-OH position of the first transcribed nucleotide of the viral mRNA cap, transforming the Cap-0 structure into a Cap-1 structure [3]. This modification is a sophisticated strategy for immune evasion, as it allows the viral RNA to mimic host mRNA and avoid detection by cytoplasmic pattern recognition receptors such as MDA5 and IFIT1 [4]. Without this methylation, the host's innate immune system recognizes the viral RNA as foreign, triggering a robust interferon response and inhibiting viral translation [5]. Consequently, nsp16 is a significant therapeutic target; inhibiting its activity could potentially sensitize the virus to the host's natural defenses and reduce viral pathogenicity [6]. Therapeutic development focuses on small molecules that compete with the SAM donor or the RNA binding site, though achieving selectivity over human methyltransferases remains a primary challenge.

Other names

Non-structural protein 16nsp162'-O-MTasensp16/nsp10 complexmRNA 2'-O-methyltransferase

Inhibition of the 2'-O-methylation of the viral mRNA cap, preventing the conversion of Cap-0 to Cap-1, which leads to the activation of host innate immune sensors and inhibition of viral translation.