Figure 2

Substituted amino acid residues. (a) Positions of the five residues substituted in TrnSR are indicated on the structure of TrnSR binding to SRSF1 (ASF/SF2, gray). The three most conserved amino acids in those positions in the 78 metazoan TrnSR orthologs are shown on the right, with probabilities estimated from their amino acid frequencies. The residues were substituted with oppositely charged amino acids. The D750/D751 dipeptide was substituted in one construct following a previous work⁴¹. E398 and D409 are proximal, and R671 and D750/D751 are also proximal. See also Table 1. (b) The ten residues substituted in Imp13 are indicated on the structures of Imp13 binding to UBE2I (UBC9, gray) (left) or MAGOH (Mago, gray) (right). The three most conserved amino acids in those positions in the 73 metazoan Imp13 orthologs are shown with probabilities estimated from their amino acid frequencies. These residues were also substituted with oppositely charged amino acids. Two constructs have dipeptide substitutions at Y34/Y35 and K802/R803 following a previous work⁵². These residues reside in three separated regions: N-terminal region, Y34/Y35 and E73; middle, Y350, D426, Y433, and E478; and C-terminal, R748 and K802/R803. See also Table 1.