The nonstructural protein (nsp) 14 of 2019-nCoV 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.positive-stranded RNA genome of the coronaviruses is translated from ORF1 to yield polyproteins that are proteolytically processed into intermediate and mature nonstructural proteins (nsps). 2019-nCoV polyproteins incorporate 16 protein domains (nsps). The putative non-structural protein 2 (nsp2) of SARS-CoV plays an important role in viral transcription and replication, and is an attractive target for anti-SARS drug development.