In at least some coronaviruses, S1-NTD is known to be involved in binding host proteins or glycans, but coronaviruses show great diversity in their binding which presumably underlies their ability to jump between very different host species. While the role of S1-NTD Compared with the current reasonably detailed knowledge of the remarkable mechanism of cell entry involving ACE2 and changes to the spike protein on cleavage, the specific function of S1-NTD of SARS-CoV-2 has not been elucidated (at least, not by the time of writing in April 2020). As noted above, S1 in SARS-CoV-2 is now well known to have a region which is the receptor binding domain to human ACE2 but also, significantly for what follows in the text below, SARS-like coronaviruses can bind CLEC4M/DC-SIGNR C-type lectin domains on host cells. See Ref. [12] for review of the diverse receptor recognition mechanisms of coronaviruses up to 2015, which represented the body of understanding until the COV-19 pandemic. Bovine coronavirus is an example of a coronavirus for which it seems clear that S1-NTD has an established glycan-binding function. Although the structure of a sugar-bound Bovine CoV S1-NTD was not available, some conclusions could be reached by researchers using structure-guided mutagenesis and comparisons with different coronaviruses. As well as evidence in 2008 linking hemagglutinin-esterase to the S1 domain of at least some coronaviruses [9], Zhang and Yap [13] had reported in 2004 a rational 3D model for S1 domain of SARS-CoV spike protein by fold recognition and molecular modeling techniques, and there they noted a suggestive structure similarity between S1 protein and influenza virus neuraminidase [14]. This opened up the possibility for those authors that existing anti-influenza virus inhibitors and anti-neuraminidase antibody could be used as a starting point for designing anti-SARS drugs, vaccines and antibodies [14].