Alignment of X-ray and NMR structures of the Cyanovirin-N. Conformation of the Cyanovirin-N dimeric form depends on the molecular environment. (a) X-ray (d1l5ba_) and (b) NMR (d1l5ea_) structures have different conformations of the "hinge" region (PRO51-ASN53) (c). To fully analyze the similarity of the two structures it is necessary to abandon the rigid-body approach. The regions on both sides of the "hinge" have to be superimposed separately. DEDAL accomplishes this by extending local similarities in both regions and effectively defining the "hinge" as the boundary between them.