Coronavirus Spike Protein Sequences from NCBI Virus

For the study of taxonomic classification of coronaviruses across all genera (Alpha-, Beta-, Gamma-, and Deltacoronavirus), we can use spike protein sequences downloaded from the NCBI Virus website, \url{https://www.ncbi.nlm.nih.gov/labs/virus/vssi/}. The spike protein sequences used in this study were downloaded on November 21 and 27, 2021 using search terms such as ``spike'', ``S1 protein'', ``S2 protein'', and ``S protein'', in order to download as many spike protein sequences as possible.