Key mutation sites in the SARS-CoV-2 spike protein modulate antibody and ACE2 affinity An allosteric center or site is one where a molecule other than the substrate to the protein can bind, altering the conformation of the protein. A paper recently uploaded to the preprint server bioRxiv* by researchers at Chapman University in California (Feb 22nd, 2021) utilized computational methods to screen severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) mutants for affinity with the angiotensin-converting enzyme 2 (ACE2) receptor and monoclonal antibodies REG10987 and REG10933. The analysis allowed the group to identify allosteric centers that mediate long-range communication in the protein. The group suggests that it is these centers that allow the spike protein of SARS-CoV-2 to act in such a versatile manner, modulating the response to antibodies while conserving ACE2 affinity.