From the global outbreak of SARS-CoV caused infection disease in 2003, coronaviruses (CoVs) are known to be a great threat to the human health. Recently, a new SARS-like coronavirus, human betacoronavirus 2c EMC/2012 (HCoV-EMC), has been identified and the appearance of this new CoV raises concerns that a new spread of CoV may occurs in the future. By solving the crystal structure of HCoV-EMC main protease with a wide-spectrum anti-CoV inhibitor N3, we confirmed that that N3 blocks the function of HCoV-EMC main protease through a similar mechanism to other CoVs. Together with the good pharmaceutical features, N3 is conceivable to be effective to HCoV-EMC and other CoVs appearing in the future. These findings make it convincing that CoVs will not be a threat to human health.

In the year of 2012, a new respiratory illness similar to severe acute respiratory syndrome (SARS) that spread globally in 2003 and infected over 8,000 people with more than 800 fatalities (Li et al., 2010), was identified in Europe, the Middle East and Hong Kong. The