Fig. 2: Structure of NatA at the distal site.
From: Multi-protein assemblies orchestrate co-translational enzymatic processing on the human ribosome
NatA binding to the peptide tunnel exit (PTE) is shown for the ternary NatA-MAP2-80S assembly, with the cryo-EM map around NatA indicated in the central panel. The long and flexibly linked ribosome interacting Naa15 helix (α34) anchors the NatA complex via electrostatic interactions mainly with the phosphoribose backbone at kink-loops of (a) ES7L(A) and (b) ES44L. c The first Naa15 TPR1 (helices α1 and α2) touches down on the ribosomal surface in a hinging movement on top of 28S rRNA helices H19 and H24 in proximity to uL24 (violet). Again, contacts involve strong electrostatic interactions. The positions of positively charged residues are highlighted in a darker shade of blue. d In addition, Naa10 engages in transient interactions with helix α3 of uL24 (labeled), involving two extended loop regions.
