| 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 |
|---|---|---|---|---|---|---|---|---|---|---|
| 2C44-K-2 | K | K⁺ | E2Q4 | GLN.GLU. | GLN.GLU. | ✔ | 6 | 6 | 2 | ✔ |
| 2O1J-CA-1 | CA | Ca²⁺ | E2Q4 | GLN.GLU. | GLN.GLU. | ✔ | 6 | 6 | 4 | ✘ |
| 1G1I-CA-1 | CA | Ca²⁺ | E2Q4 | GLN.GLU. | GLN.GLU.HOH. | ✔ | 6 | 8 | 4 | ✘ |
| 1G1J-SR-1 | SR | Sr²⁺ | E2Q4 | GLN.GLU. | GLN.GLU.HOH. | ✔ | 6 | 8 | 4 | ✘ |