Chemical modifications, ions and water molecules in the sub-2 Å resolution structure of the human 80S ribosome

Abstract

Using next-generation cryo-EM and mass spectrometry, we identified 235 chemical modifications in the sub-2 Å resolution structure of the full human 80S ribosome. The newly identified rRNA modifications were found to create new hydrogen bond patterns for riboses and uridines. Ion visualization revealed that Mg2+-associated water molecules are variably substituted by side chains. This study provides the molecular basis for the stabilization of A–U or A–Ψ base pairs and RNA–protein interactions.