Biological role of the two overlapping poly(A)-binding protein interacting motifs 2 (PAM2) of eukaryotic releasing factor eRF3 in mRNA decay

Binding of eRF3 to PABC with chemical exchange between complexes PABC–PAM2-N and PABC–PAM2-C. (A) Spectral overlay of ¹H–¹⁵N HSQC of ¹⁵N-labeled PABC in the presence of eRF3a fragments. Spectra in the presence of eRF3a fragments, residues 64–82 (black), 73–94 (red), and 64–94 (green). (B) Spectral changes of ¹H–¹⁵N HSQC of ¹⁵N-labeled PABC upon sequential additions of eRF3a (64–94). The molar ratios are indicated. (C) Schematic drawing of the chemical exchange between complexes PABC–PAM2-N and PABC–PAM2-C. PAM2-N (purple); PAM2-C (red); the overlapping regions (yellow).