Figure 4. Human and yeast exosome cores: differential binding to the exoribonuclease.

(A-B) Interactions made by the PIN region (A) and the RNB region (B) of the exoribonuclease (pink) with the proteins of the central scaffold (shown in the same colors as in Figure 3). The figures show the comparisons between the human cryo-EM structure (upper panels) and previous yeast X-ray structures (lower panels) (Makino et al., 2015, 2013). The human complex shows fewer interactions at the structural level as compared to the yeast complex. (C) Size exclusion chromatography experiments showing the weaker binding of hDIS3 to hRRP41-hRRP45 as compared to that of the yeast orthologues.