"Three coronaviruses have emerged over the last 20 years as serious human pathogens: SARS-CoV was identified as the causative agent in an outbreak in 2002-2003 outbreak, Middle East respiratory syndrome (MERS) CoV emerged in 2012 and the novel coronavirus SARS-CoV-2 emerged in 2019-2020.These are all enveloped, single-stranded positive-sense RNA viruses whose genomes and protein structures are highly conserved" (Alexander SP, Ball JK, Tsoleridis T).
Alexander SP, Ball JK, Tsoleridis T. Coronavirus (CoV) proteins (version 2020.5) in the IUPHAR/BPS Guide to Pharmacology Database. IUPHAR/BPS Guide to Pharmacology CITE. 2020; 2020(5). Available from: https://doi.org/10.2218/gtopdb/F80/2020.5.