RHS proteins contain extended repeat regions. These repeats often appear to be involved in ligand binding. Note that this model may not find all the repeats in a protein and that it covers two RHS repeats. The 3D structure of an RHS-repeat-containing protein (the B and C components of an ABC toxin complex) has been determined. The RHS repeats form an extended strip of beta-sheet that spirals around to form a hollow shell, encapsulating the variable C-terminal domain.