Fig. 1

Hierarchy of zone attributes. a Zone primary structures with proteins as pink shapes and lipids as circles with two tails or one tail attached to protein. b Secondary structures in either side or top views with proteins in pink and lipids as circles, ovals, or hexagons representing free, loosely bound, and strongly bound to protein, respectively. c Tertiary attributes illustrated on a bilayer with one leaflet coloured blue and the other green. d Quaternary attributes illustrated by merging and separating zones