Peptide binding on IgFLNa20–21.

A A model of three conformational states for the IgFLNa20–21 mechanosensor module. The compact conformation (I) domain pair interactions are disrupted by the replacement of the A strand. In open conformations (II) the domains move freely in relation to each other, but peptide ligand binding (III) restricts the movements. B Sequence alignment of the peptides known to interact with IgFLNa21 and whose IgFLN complex structures have been determined. C Superimposition of IgFLNa21 (green) structures in complex with peptides: migfilin (yellow), β7-integrin (cyan) [16], β2-integrin (orange) [19], and CFTR (grey) [20]. Prolines (shown as sticks) at C termini bend the peptides towards the top of IgFLNa21. The conformation of the CFTR peptide is influenced by crystal packing [20].