Comparison of β-prism domains from VCC, Bap1, and RbmC.

(A) Crystal structure of the heptameric pore state of VCC [62] showing β-prism domains in orange and D617 (essential for carbohydrate binding) indicated by magenta spheres. (B) Schematic showing approximate locations of β-prism domains (shaded orange) in VCC, Bap1, and RbmC. Red box in Bap1 indicates the approximate location of the 58 amino acid insertion of unknown function. (C) Sequence alignment produced using MEGA7 [63] and ESPript v. 3.0 (http://espript.ibcp.fr) [64] of four V. cholerae β-prism domains. Identical residues are shaded red whereas similar residues are indicated by red type. The second RbmC β-prism domain contains a five-amino acid insertion near the glycan-binding pocket (shaded blue). VCC D617 is marked by a purple asterisk. Structure figures made using the PyMOL Molecular Graphics System, Version 1.8 (Schrödinger, LLC).