Figure 2. hRpn2 zippers along an hRpn13 surface with extensive interactions and a proline-rich contact surface.

(a,c) Ribbon diagram of hRpn13 (periwinkle blue) with heavy atoms at the hRpn2 contact surface displayed. All hRpn2 heavy atoms are shown (light orange) with dashed lines representing intermolecular NOE interactions involving (a) hRpn2 P942-P945 and P947 and (c) hRpn2 F948 and Y950. Nitrogen, oxygen and sulfur side-chain atoms are displayed in blue, red and yellow, respectively. The orientation in (a) is selected to highlight interactions involving hRpn13 W108. (b) Selected intermolecular NOEs between hRpn2 and hRpn13. Selected regions from a ¹H, ¹³C edited NOESY experiment acquired with 0.7 mM ¹⁵N, ¹³C-labelled hRpn2 (940–953) and equimolar unlabelled hRpn13 Pru (upper panel) and selected regions from a ¹H, ¹³C half-filtered NOESY experiment acquired with 0.7 mM ¹⁵N, ¹³C-labelled hRpn13 Pru and equimolar unlabelled hRpn2 (940–953) (lower panel).