The forceÀdistance measurements quantify the molecular dimensions of the DC-SIGNR-Man 9 GlcNAc 2 complex and thus provide direct evidence for an extended configuration of the extracellular domain of DC-SIGNR. At initial contact, the length of the 7-repeat form of DC-SIGNR complexed with the glycan is D C = 26.6 ( 0.8 nm ( Table 1) . Modeling of the structure of the extracellular domain of DC-SIGNR bound to a Man 9 GlcNAc 2 oligosaccharide 17 suggests that the overall length of the ligand complex of the DC-SIGNR fragment used in the forceÀdistance measurements would be 26.5À27.0 nm, which agrees quite well with the measurements reported here. The crystallographic and forceÀdistance measurements also agree well with hydrodynamic measurement on the extracellular domains and the isolated neck domains. 19, 32 The equilibrium thickness is smaller at ∼25 nm but still comparable to the model prediction.