– The nonstructural protein (nsp) 14 of SARS-CoV 2 was identified as a cap (guanine-N7)-methyltransferase (N7-MTase). Nsp14 of coronaviruses two different activities: an exoribonuclease activity acting on both ssRNA and dsRNA in a 3′ to 5′ direction and a N7-guanine methyltransferase activity. It may be involved in the proof-reading ability during the viral RNA replication and transcription. GTP, dGTP as well as cap analogs GpppG, GpppA and m7GpppG could be methylated by nsp14.