| Code | Name | Deposits | Targets | Ligand Type |
|---|---|---|---|---|
| XC4 | 1 | 1 | biological | |
| X8Z | l-captopril | 1 | 1 | biological |
| X8Z | l-captopril | 1 | 1 | crystallization |
| X77 | X77 | 1 | 1 | biological |
| VCA | 1 | 1 | biological | |
| VBY | 5-(acryloylamino)-2-methyl-N-[(1R)-1-(naphthalen-1-yl)ethyl]benzamide | 2 | 1 | biological |
| V7G | unknown | 1 | 1 | biological |
| UVW | acetylphosphate | 2 | 2 | biological |
| UVC | uridine-2',3'-vanadate | 1 | 1 | biological |
| UTP | 1 | 1 | biological | |
| URI | uridine | 1 | 1 | biological |
| URE | urea | 1 | 1 | crystallization |
| URA | uracil | 1 | 1 | other |
| UNX | Unknown atom | 4 | 2 | other |
| UNX | Unknown atom | 9 | 3 | crystallization |
| UNX | Unknown atom | 2 | 2 | biological |
| UNM | 7-[(cis-4-aminocyclohexyl)amino]-5-bromo-1-benzofuran-2-carboxylic acid | 1 | 1 | biological |
| UNL | 2 | 1 | biological | |
| UNL | 3 | 2 | crystallization | |
| UNK | unknown | 2 | 2 | modified residue |