Lactoferrin ribbon diagram

Within each lobe there is a further subdivision into two separately folded domains. This is shown schematically in Fig. 3 and can be clearly seen in the ribbon diagram of Fig. 4. The domains in the N-lobe of lactoferrin are labeled N1 (residues 1-90 and 252-333) and N2 (residues 91-251), with the equivalent C-lobe domains being Cl (residues 345-433 and 596-691) and C2 (residues 434-595). This subdivision into domains also has a crucial functional significance as the cleft separating the two domains of each lobe houses the metal binding site, and the domain structure has msqor implications for mechanisms of binding and release this is explored further in Sections III.B.2-III.B.4. 

Fig. 4. Ribbon diagram of human diferric lactoferrin, showing the organization of the molecule, with the N-lobe above and C-lobe below. The four domains (Nl, N2, Cl, C2), the interlobe connecting peptide (H), and the C-terminal helix (C) are indicated. The glycosylation sites in various transferrins are shown by triangles and numbered (1, human transferrin 2, rabbit transferrin 3, human lactoferrin 4, bovine lactoferrin 5 chicken ovotransferrin). The interdomain backbone strands in each lobe can be seen behind the iron atoms. Adapted from Baker et al. (82), with permission.

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