HEB
PCM
| Residue type | PCM type | Category | Position | UniProt PTM accession | Entries in PDB |
| ASP | None | Heme/heme-like | Amino-acid side chain (Any position) | 1 | |
| CYS | None | Heme/heme-like | Amino-acid side chain (Any position) | 1 | |
| GLU | None | Heme/heme-like | Amino-acid side chain (Any position) | 1 | |
| HIS | None | Heme/heme-like | Amino-acid side chain (Any position) | 6 | |
| ASP | None | Metal coordination | Amino-acid side chain (Any position) | 3 | |
| CYS | None | Metal coordination | Amino-acid side chain (Any position) | 5 | |
| GLU | None | Metal coordination | Amino-acid side chain (Any position) | 4 | |
| GLU | None | Metal coordination | Amino-acid side chain (Any position) | 4 | |
| HIS | None | Metal coordination | Amino-acid side chain (Any position) | 63 | |
| MET | None | Metal coordination | Amino-acid side chain (Any position) | 7 |
