Figure 5: Models of MERS-CoV and SARS-CoV S trimers bound to their receptors.

The models were built by superimposition of the S trimer structures with the RBD-receptor complex structures through the RBD domains. The MERS-CoV S trimer can cross-link the dimeric CD26 receptor during the binding (a), whereas the SARS-CoV S trimer can bind one monomeric ACE2 receptor (b).