Surface representations of the fZP1-C/fZP1-N homomeric interface colored by evolutionary conservation of amino acid positions in ZP1 and the related ZP modules of ZP2 and ZP4 (using a spectrum ranging from deep magenta [highest conservation] to light green [lowest conservation], with yellow indicating residues with a low-confidence conservation level; top), or by electrostatic potential (using a spectrum ranging from red [2.5 kT/e] to blue [+2.5 kT/e] through white [0 kT/e]; bottom). Panels are shown in an open book representation, with black dashed ovals indicating the moieties of the interface. Inset, close-up view of the fZP-N1 surface from the direction of the eye symbol, highlighting charge-related interactions between fZP1-N D294, E348, D360, and fZP1-C R437, R488.
