unds were barely active against 2′-O MTases of several flaviviruses or SARS-CoV but surprisingly, seven of them showed efficient and specific inhibition against SARS-CoV N7-MTase (nsp14) in the micromolar to submicromolar range. The most active nsp14 inhibitor identified is as potent as but particularly more specific than the broad-spectrum MTase inhibitor, sinefungin. Molecular docking suggests that the inhibitor binds to a pocket formed by the S-adenosyl methionine (SAM) and cap RNA binding sites, conserved among SARS-CoV nsp14. These dinu