(A) Sequence alignment of COVID-19 RBD subdomain-1 (319th to 591st) amino acid (top row) with the bat and SARS-CoV spike protein (middle and bottom row) that were fetched from BLASTp results of the COVID-19 virus RBD subdomain-1 (319th to 591st) amino acids. Note horizontal arrows that show areas of contrast between the sequences. (A1) Homology modeling of the COVID-19 virus RBD subdomain-1 (319th to 591st) amino acid developed a template (6vsb.1. A)-based model of the COVID-19 virus spike glycoprotein. (B). Homology modeling of the COVID-19 virus RBD subdomain-1 (319th to 591st) amino acid developed a template-(5x5b.1.A) based model of the prefusion structure of SARS-CoV spike glycoprotein in conformation 2 (B1) with 73.96% sequence identity.