Fig. 4

Trichuris muris p43 protein possesses extensive surface-connected internal cavities. Ribbon representation of the X-ray crystal structure of p43 showing a mix of alpha helices (coils) and extended/β structures (arrows) along with unstructured chains. (A) Two molecules as in crystal structure asymmetric unit (PDB 6QIX); cartoon ribbon for chains, surfaces coloured for electrostatic potential of their walls, culled to show only internal cavities, charges indicated red for negative, blue positive, white neutral. Cavities exhibit a complex mix of internal surface charges and shapes, and the cavities of the duplicated/repeat domains appear to have diverged. (B) Rotation of one molecule, again showing the diversity of cavities and the lack of repetition of types. Molecular display using PyMOL.