Fig. 4: p97 remodeling interactions by UBXD1 helical lariat and VIM–H4.
a, Closed state map (from p97–UBXD1meta) showing density for the UBXD1 helical lariat (orange) and UBX (yellow) encircling the P6 NTD with Lα2, Lα3 and Lα4 interacting along the P6–P1 interprotomer interface. b, Expanded view showing Lα3 and Lα4 (orange) contacts with P6 across the NTD, D1 and D2, including putative electrostatic interactions (dashed lines). c, View of Lα2 interactions involving hydrophobic packing into the NTD using F292 and F293. d, View of the P6–P1 interface showing key contacts by Lα3 with the D1 α12 helix of protomer P1. e, View of Lα3 and Lα4 intra-lariat contacts (between R313, R318 and E326) and contacts with D2 (by L317 and T319), stabilizing the helical lariat. f, Unsharpened map of p97–UBXD1H4, showing density for H4 (green) adjacent to the VIM (brown) and along the P6–P1 interface. Shown below is an expanded view of the VIM–H4 sequence, featuring only a short, seven-amino acid linker connecting the two helices. g, Modeled view (see Extended Data Fig. 7c) of helix H4 interacting across the D2 domains at the P1–P6 interface from p97–UBXD1H4 (P1, dark blue; P6, light blue), overlaid (by alignment of the P1 D2 large subdomain) with p97–UBXD1closed (gray, showing conformational changes at the P6–P1 interface including displacement of P6 helix α5′ (red) and large rotation of P1 α12′).
