Complexes. Finally, we consider four protein-ligand complexes: 181L:benzene (Fig. ), 100 1LI2:phenol, 101 1HSG:indinavir (Fig. ), 102 and 1O44:(C 34 H 35 N 3 O 9 ). In the latter complex, the ligand is a malonic acid derivative known as RU85052 and we henceforth refer to this system as 1O44:RU85052. The indinavir and RU85052 complexes involve much larger ligands as compared to benzene and phenol, and the computed values of ∆E int are correspondingly larger for these two systems.