Figure 2: Two subgraphs corresponding to recurrent substructures extracted from a dataset of 38 proteins (including the HFE(human) hemochromatosis protein) of the immunoglobin C1-set domains family. All the 38 proteins were transformed into graphs using PG-converter, then a frequent subgraph discovery was performed to discover the recurrent substructures with a minimum support threshold of 30%. This figure highlights the mapping of both subgraphs on the original 3D-structure of the HFE(human) hemochromatosis protein.