FIGURE 4. 3D models of C14orf166 (A ) and influenza DkPen PA proteins (B ) predicted by AlphaFold (C14orf166 # Q9Y224) and I-TASSER algorithm, respectively. The carboxyl-terminal and amino-terminal ends of the proteins are shown in red and blue, respectively.
Model C69-1 (Figure 3), the c-terminal peptide of C14orf166 consisting of 69 amino acid residues and the model of the DkPen virus PA protein (Figure 4B) were matched with the online protein-protein docking server using the ClusPro docking algorithm. Among the many prominent interaction models, considering the influenza A virus RdRP complex structure 28 (PDB # 6QPF) (the regions of the PA protein interacting with PB2 and PB1 were eliminated) and the inability to detect C14orf166 among the host proteins interacting with the amino-terminal of viral PA in the Y2H screening assay (in which we used amino-terminal half of the PA protein as a bait-data not shown), the region with the highest accumulation for C69-1 on the PA protein was determined. It was observed that model C69-1 accumulates in the carboxyl-terminal half of the viral PA protein involving amino acid residues mostly between positions 610 to 630 in most of the docking models as shown in Figure 5. One salt bridge and 11 hydrogen bonds were defined in the interaction area of the models.