A regional outbreak of pneumonia in Wuhan, Hubei Province of China in late 2019 was associated with a novel coronavirus. Rapid release of genomic data for the isolated virus enabled the construction of first-generation homology models of the new CoV 3CLpro cysteine protease. Whilst the overall viral genome was most closely associated with bat coronaviruses, the main protease is most closely related (96% identity) to SARS CoV protease.