Design and Pharmacological Chaperone Effects of N-(4′-Phenylbutyl)-DAB Derivatives Targeting the Lipophilic Pocket of Lysosomal Acid α-Glucosidase

This study provides the first example of a strategy to design a practical ligand toward lysosomal acid α-glucosidase (GAA) focusing on N -alkyl derivatives of 1,4-dideoxy-1,4-imino- d -arabinitol (DAB). The optimized N -4′-( p -trifluoromethylphenyl)butyl-DAB ( 5g ) showed a K i value of 0.73 μM, which was 353-fold higher affinity than N -butyl-DAB ( 3f ) without a terminal phenyl group. Docking analysis showed that the phenyl part of 5g was accommodated in a lipophilic pocket. Furthermore, the p -trifluoromethyl group effectively suppresses the fluctuation of the phenyl group, allowing it to produce a stable bonding form with GAA. 5g increased the midpoint of the protein’s protein denaturation temperature ( T m ) by 6.6 °C above that in the absence of the ligand and acted as a “thermodynamic stabilizer” to improve the thermal stability of rhGAA. 5g dose-dependently increased intracellular GAA activities in Pompe patient’s fibroblasts with the M519V mutation; its effect was comparable to that of DNJ, which is under clinical trials.