As is to some extent customary in the field, three letter codes (such as GLY for glycine) are used for the amino acids in the molecular graphics figures; these codes are fairly self-evident at least in the direction of deducing the full name of the amino acid being represented. There was also use of data and the associated graphics tools in the Protein Data Bank (PDB) at https://www.rcsb.org/and in Japan https://pdbj.org/which was used for Fig. 1.