Fig. 4: VIRMA adopts a horse-shaped conformation clamped by WTAP homodimer.

a Structure of VIRMA in two different views. b–d Structure and packing orientation of different domains in VIRMA. ARML repeats (1–20) are shown in different colors. Curved arrows indicate the inter-repeat packing orientation. Connect helix-1 and -2 separate the Belly, Chest, and Back domains while changing their inter-repeat packing orientation. The noncanonical interaction between ARML10 and 11 separates the Back and Neck domains. Head and Neck domains are divided by Halter domain. e Details of the inter-repeat interactions between ARML repeats 10 and 11, corresponding to the magenta box in d. f, g Surface presentation of VIRMA in the HWVZ complex. The surface of VIRMA is colored by electrostatic potential (f) and sequence conservation (g). ZC3H13 and WTAP are shown in cartoon mode. h Intermolecular contacts between WTAP-b (H1’) and Back domain of VIRMA, corresponding to gold box in f and g. i Details of interactions between WTAP H4/H4’ and Belly-Chest domain of VIRMA, corresponding to green box in f and g. j Halter domain tied the WTAP L1/L1’ to the Neck domain of VIRMA. Intermolecular contacts between the WTAP homodimer and VIRMA around L1/L1’, corresponding to the cyan box in f and g.