Abstract
Four of five different monoclonal antibodies (mAbs) that have been crystallized in complex with the receptor binding domain (RBD) of the SARS-CoV-2 spike protein (S) have remarkably similar primary and secondary loop structures at the heavy chain complementarity-determining regions (HCDR) 1 and 2. All these reports give a structural basis for the deceptively difficult problem of accurate peptidomimetic loop mimic design.