For lung disease, augmentation therapy is the only specific regiment that is thought to slow down disease progression, although this still requires formal proof through well-controlled clinical trials . As these treatments are expensive, labor intensive and associated with side effects, the need for novel treatments are indeed in high-demand. With Z-��1AT polymerization being responsible for the development of the disease, blocking its aggregation by small molecules appears to be a promising strategy to cure Z-��1ATD. Here we report an integrated in vitro and in silico approach which allows discovering and characterizing small molecules that disrupt the VE-822 pathological polymerization of Z-��1AT. The in vitro microplate assay, which enables the identification of small molecules able to block the insertion of a modified 6-mer peptide into the s4A cavity, provides quantitative data with reproducibility, sensitivity and rapid throughput. Our results validate the utility of the in vitro screening assay and identify S- -6-thioguanosine as inhibitor of Z-��1AT polymerization. With a molecular weight of 434.43 Da, 4 H-bond donors, 11 H-bond acceptors and a low lipophilicity coefficient , this compound presents a drug-like profile according to the Lipinski criteria . From IC50 determination and structure-activity relationship studies, we also found one of its structural homologues which differs by a single amino group and does not prevent aggregation. This suggests that an interaction with the amino group may be important to counteract the insertion of the modified 6-mer peptide. The microplate assay has been designed to identify any inhibitor that can impede the insertion of the RCL into the s4A cavity; compounds may bind at several locations within the s4A cavity or even bind outside of the s4A cavity causing a conformational rearrangement that still precludes RCL insertion. To characterize the binding of S- -6-thioguanosine, molecular 1805787-93-2 docking studies were carried out at several potential binding locations, in and outside the s4A cavity. Previous studies have used molecular docking to investigate the binding of small molecules into experimentally resolved structures at
