Figure 2

AFM images of E-cad-Fc molecules in a PBS solution containing 0.9 mM Ca²⁺ at room temperature and their structural models. (a) AFM image of E-cad-Fc molecules. E-cad-Fc molecules were observed in various conformations (scale bar 100 nm). (b,d) Magnified AFM images of E-cad-Fc monomer-like structures of the points b and d in (a) (scale bar 20 nm). (c,e) E-cad-Fc monomer models constructed from the AFM measurement results of (b) and (d). The orientation and tilt of the Fc domain are arbitrary due to insufficient resolution of AFM image. (f) Magnified AFM image of E-cad-Fc molecules of the point f in (a) (scale bar 20 nm). Three E-cad-Fc molecules appear trans-bonded (blue arrow) in the EC1 domain. EC domains (blue dotted circle) and Fc domains (red arrow) are distinguishable. (g) E-cad-Fc model constructed from the AFM measurement results of (f). (h) EC domain model. The five EC domains are curved such that the long axis of EC1 is approximately perpendicular to the long axis of EC5^46,47,48. (i–k) Magnified AFM images of E-cad-Fc binding structures of the molecules i, j and k in (a) (scale bar 20 nm).