, and 1-palmitoyl-2oleoyl-sn-glycero-3-phospho-L-serine -POPS (PS) lipids per layer, respectively, giving 200 lipids in total. Selected lipid concentrations should be close to physiological conditions inthe endoplasmic reticulum (ER) . For this purpose, UL49.5 proteins were inserted in the lipid bilayer model in such a way that the whole TM fragments were placed inside the bilayer. Then, the obtained system was surrounded by 25Å of water (15510 molecules) from both sides of the lipid bilayer to prohibit interactions between periodic images.