Structural domains comprising this superfamily share the structure of the N-terminal domain of Saccharomyces cerevisiae's Hri1 (Hrr25-interacting protein 1, YLR301w), a non-essential protein named for its interaction with the yeast protein kinase Hrr25. It has also been shown to also interact with Sec72p, although it does not seem to be involved in protein translocation into the ER. This N-terminal domain of Hri1p contains a tandem repeat of a structural unit that forms a beta-barrel with structural similarity to nitrobindin. It is involved in homodimerization and it may also contain a ligand binding site PMID:22525751.