| Id | Element | Ion | Binding family | Amino acids or nucleotide residues names | All bound residues | Is homomer | Number of bound amino acids or nucleotide residues | Number of all bound residues | Number of coordinating chains | Representative |
|---|---|---|---|---|---|---|---|---|---|---|
| 3EPI-NA-1 | NA | Na⁺ | C1I2K1 | DC.ILE.LYS. | DC.ILE.LYS. | ✘ | 4 | 4 | 2 | ✔ |
| 3EPI-NA-2 | NA | Na⁺ | C1I2K1 | DC.ILE.LYS. | DC.ILE.LYS. | ✘ | 4 | 4 | 2 | ✔ |