Development of biochemical/biophysical assays to identify SmBRD3 BRD ligands required the recombinant expression of SmBRD3(1), SmBRD3 (2), and a construct that contained both bromodomains and the residues that link them [SmBRD3 (1,2)]. While we were able to select and produce stable constructs of SmBRD3(2) and SmBRD3 (1,2) in good yields (Figures , Table ), this was not possible for SmBRD3 (1). Analysis of the full protein structure predicted by AlphaFold indicates that the helix comprising residues 617-638 and the subsequent disordered residues 639-660 form intra-protein interactions in the region between SmBRD3(1) and SmBRD3(2) (Figure ). We propose that these interactions are required to stabilize SmBRD3(1) (Figure ), and while they can be compensated for by other hydrophobic interactions in SmBRD3 (1,2), this is not possible in SmBRD3(1) rendering it unstable when expressed alone.