Figure 2. Cryo-EM structure of Dvl2 DIX filaments reveals anti-parallel double helices stabilized by intra- strand (head-tail) and inter-strand contacts.
(A) Cryo-EM image of purified Dvl2 DIX filaments. (B) Final sharpened cryo-EM map with helical symmetry imposed, with the two antiparallel strands shown in green and blue contours. (C) Final model of the Dvl2 DIX anti-parallel double helix, containing 12 subunits. The secondary structure elements are marked in the upper brown copy. The schematic diagram on the right shows the antiparallel structure, with each subunit represented as a triangle colored as in (B). (D) A portion of the final cryo-EM map (wire frame) and model showing a head-to-tail interface involving Y27 (head) packing against F56 and K68 (tail).