Localization of Arg98 in the membrane-embedded homology-based model of hVKORC1 protein. This figure illustrates the spatial positioning of the ER retention motifs with respect to the ER membrane in the membrane-embedded homology model of hVKORC1 protein. The upper 2 panels show the membrane-embedded hVKORC1 protein in a simulation cell. The ER membrane is represented with ball models on the right and by its molecular surface (yellow colored) on the left. The hVKORC1 protein is represented in ribbon form, whereas the residues, which are part of the ER retention motifs, are represented as stick models in red (di-lysine motif, Lys159_His163) and blue (di-arginine motif, Arg98_Arg100). The lower panel is a closer look at both motifs. The water molecules within the simulation box are represented by their molecular surface in blue.