a, Structural superposition of apo-FERECD (cyan), apo-ANX1ECD (blue) and apo-ANX2ECD (green). Structural alignment of apo-ANX1ECD(26–410) or apo-ANX2ECD (27–414) with apo-FERECD(29–423) with root mean square deviation (r.m.s.d.) 0.876 and 0.754 Å, respectively. α-helix 3 and β-sheet 16 are labelled. b, Structural comparison of the malectin domains of FERECD (cyan/light blue) with malectin–nigerose (NGR) (grey and yellow, respectively) complex from X. laevis (PDB code 2K46). The malectin domain B of FER (residues 197–447) is used as the template for alignment with malectin domain A of FER (residues 27–196) with an r.m.s.d. of 4.065 Å, and with malectin (residues 1–190) with an r.m.s.d. of 16.157 Å. Black box and arrow show the LLG2-binding region in malectin domain B of FERECD. The red box marks the NGR-binding pocket of malectin–NGR. c, Saccharide-recognizing residues are not conserved among malectins. Sequence alignment of malectin domain A and domain B from FER, and malectin from X. laevis. Red dots mark residues that form an NGR-perception pocket in malectin. d, Structural superposition of FERECD(29–423) and RALF23–LLG2–FERECD(29–423) with an r.m.s.d. of 0.441 Å. Colour codes are indicated. e, The N-terminal region (residues 4–17, brown) of RALF23 binds to a surface groove of LLG2 (shown in electrostatics). Important residues of RALF23 recognized by LLG2 are indicated. f The 2Fo-Fc electron density map (blue mesh) around the N-terminal region of RALF23 (residues 4–17) in the final refined model contoured at 1.2σ (using COOT). The structural model of the N-terminal region is highlighted within the dashed cyan frame, and the LLG2-interacting residues are labelled in white. g, FERECD (cartoon in cyan) interacts with both LLG2 (surface in purple) and RALF23 (surface in brown). Some secondary structures of FERECD are indicated.