The crystal structures of five coronavirus S1 domains complexed with their respective receptor have been determined:

• β-genus SARS-CoV S1-CTD complexed with human ACE2
• β-genus MERS-CoV S1-CTD complexed with human DPP4
• α-genus HCoV-NL63 S1-CTD complexed with human ACE2
• α-genus PRCV S1-CTD complexed with porcine APN
• β-genus MHV S1-NTD complexed with murine CEACAM1
• β-genus BCoV S1-NTD by itself has been determined with its sugar-binding site identified through mutagenesis