The 2?-O-ribose methyltransferase (2'-O-MT) catalyzes the methylation of Cap-0 (m7GpppNp) at the 2'-hydroxyl of the ribose of the first nucleotide, using S-adenosyl-L-methionine (AdoMet) as the methyl donor. Therefore NSP16 plays an essential role in viral mRNA cap 2?-O-ribose methylation which is essential to evade the hosts' immune system. The presence of the N7-methyl guanosine cap is a prerequisite for NSP16 binding. The association of NSP10 with NSP16 enhances NSP16's 2'-O-MT activity, possibly through enhanced RNA binding affinity.

SSQAWQPGVAMPNLYKMQRMLLEKCDLQNYGDSATLPKGIMMNVAKYTQLCQYLNTLTLAVPYNMRVIHFGAGSDKGVAPGTAVLRQWLPTGTLLVDSDLNDFVSDADSTLIGDCATVHTANKWDLIISDMYDPKTKNVTKENDSKEGFFTYICGFIQQKLALGGSVAIKITEHSWNADLYKLMGHFAWWTAFVTNVNASSSEAFLIGCNYLGKPREQIDGYVMHANYIFWRNTNPIQLSSYSLFDMSKFPLKLRGTAVMSLKEGQINDMILSLLSKGRLIIRENNRVVISSDVLVNN

298 aa; 150 kDa