Finally, grid channels can represent the different chemical elements or even distinct physicochemical properties of the atoms, such as hydrophobicity, hydrogen bond acceptance or donation capabilities, ionizability, and partial atomic charges . Fig. illustrates channels for carbon and hydrogen atoms of the ligand using the space-filling occupancy model described above. Our voxel representation uses specific channels for representing carbon, hydrogen, oxygen, nitrogen, and sulphur atoms. An additional channel is employed to include all other elements that may occur in a molecule (e.g., halogen atoms). We also use a channel for representing the total excluded volume of the molecule, irrespective of individual atomic properties. These channels are applied to individual molecular entities separately (either protein or ligand) and to the whole complex (i.e., protein and ligand together in the same channel), resulting in a 21-channel grid representation. The grids are set at a 1.0 Å resolution within a 24 Å³ box centred around the ligand's geometric centre. A similar configuration of channels and grid dimensions is also employed by others in the scientific literature . It is worth mentioning that the DockTGrid software allows users to customise channel features and grid parameters freely. For instance, Fig. depicts a complete voxel representation for a protein-ligand complex from our dataset. Files of the protein-ligand complex with PDB code 5OD1 58 are used as an example. Files are presented in italics, while directories are in a standard font.