l - People

Figure 4.5: Human lactoferrin (open, apo form)
Morph ID: f964647-15593 PDB ID: 1LFG
HAG hinges: 90,91,250,251
The coloring scheme in (a) is similar to that used for Troponin C, i.e. with domains on
either side of a HAG hinge colored differently. The mobile domain spans residues 91-
250, but FlexOracle shows a slightly wider region of high energy, separated by minima at
78 and 261. This is explained by phenomena similar to those observed in Glutamine
Binding Protein, namely that the parallel strands of the linker region prefer to be in the
same fragment so as to not lose their mutual contacts.
HingeMaster makes a strong prediction for a hinge at residue 332 (all four algorithms in
agreement). This chain location does not appear in the HAG, but a search of the literature
uncovered evidence for a hinge at this location. Lactoferrin is organized into two
homologous halves, named the N and C lobes. Each of these lobes is further subdivided
into two domains: N1 and N2 in the N lobe and C1 and C2 in the C lobe. The opening of
these domains exposes an iron binding site in each lobe. The motion selected for Hinge
Atlas Gold shows the N1 domain (shown in blue) rotating relative to the rest of the
molecule exposing the binding site in the N-lobe. Thus, the HAG hinges are located
between the N1 and N2 domains. The hinge most strongly predicted by Hinge Master,
however, falls in between the C1 and N2 lobes and contributes to the movement of the
two lobes relative to each other. As in the case of Troponin C, experimental evidence is
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