Because of the computationally demanding requirements of alchemical ABFE calculations, large-scale studies have seldom been performed using such approaches. Hitherto, there have been mainly small-scale studies (involving only a handful of protein-ligand systems) focusing on the accuracy of the approach, including early studies of inhibitors to T4 lysozyme, a model system with specific binding properties comprising small aromatic inhibitors with limited rotational degrees of freedom binding to a small, buried hydrophobic or polar binding site . In the last few years, alchemical ABFE has been applied to more complicated molecular systems including bromodomains (BRDs) of the bromodomain-containing proteins, FK506 binding protein 12 (FKBP12) and others .