Virtual screening is like searching for a needle in a haystack, where the needle represents a potential inhibitor within a vast chemical space. It serves as a guide, helping researchers navigate this ever-expanding chemical universe to find compounds with optimal drug-like properties, favorable pharmacokinetics, and similarity to known active compounds in both 2D and 3D. It’s akin to piloting a shuttle through nearby clusters of molecules that show promise for a target or a group of targets. The total chemical space is staggeringly vast—estimated to be on the order of 10^60 molecules if one only considers combinations of carbon, oxygen, nitrogen, and hydrogen. This immense size makes it impossible to explore entirely, but typical chemical libraries used in virtual screening contain about 10^6 compounds, allowing researchers to focus on the most promising regions of this space. However, even with millions of molecules available, these libraries still leave much of the chemical space une...
