ure ), we see that it is not feasible for both dimers to simultaneously associate with a planar membrane. However, the ER membrane is often highly curved, which may allow the h-cisPT complex to form multiple associations. Several hints are also offered as to the mechanism by which dolichol associates with the ER membrane. We observe that the prenyl chain is capable of interfacing with the ER membrane at an immature length (Figure ). This indicates that confining the product inside the hydrophobic pocket until release, as is the case is prokaryotes, is not a viable model for h-cisPT. It has been speculated that extension of the prenyl substrate may lead to an conformation shift in the DHDDS N-terminus, as the growing prenyl chain pushes the N-terminus away from the opening of the DHDDS active site. There is some support for this in our simulations. Following the addition of a prenyl product, the N-terminus makes stronger contact with the ER membrane across all simulations, and becomes the highest-contact region of the protein(Fig. ). Associated to the ER membrane, the N-terminus appears to be unable to influence the prenyl substrate's exit from the binding pocket. This suggests that immature prenyl products may be able to form and maintain membrane contacts. This aligns with simulations, in which a 9-unit prenyl product is observed to contact the membrane. Further, in simulations with a mature dolichol, the dolichol maintained insertion into both the membrane and h-cisPT.