Table 3.

Positions used to distinguish bilayer regions (I–IV) and other features (5–8) at 298 K

Region/Label	Description	Distance from bilayer center (Å)
		POPC	POPC/chol
I	Low headgroup density	28	30
II	High headgroup density	22	25
III	High tail density	15	18
IV	Low tail density	9	8
5	MD boundaries: Z1, Z2	28	30
6	EPR region	18	21
7	EPR headgroup segment	13–18	16–21
8	Peak headgroup density	22	25

For regions, the outermost boundary is shown.