Figure 3. Structural models of the CBM of LytC and the whole enzyme.

(a) The CBM folds in a β-solenoid structure. β-Hairpins of repeating units appear differently coloured, from dark blue (p1) to purple (p9). (b) Disposition of the potential choline-binding sites. Numbers indicate the order of the hydrophobic cavities (dark grey) from the N- to the C-terminal end starting at the p2 repeat. Sites 2 and 5 are located between a short and a large repeat. (c) Different views of the model generated for the whole structure of LytC. The region comprising strands β₆–β₈ of the CM (red) interacts with repeats p7–p8 of the CBM (dark blue). The C-terminal side of the barrel, where the catalytic cavity is located, points towards the bottom of the Figure.