[gmx-users] About atom references calculating area per lipid

[Poncho Arvayo Zatarain]

hello: i´m trying to calculate area per lipid of mixed bilayer using Gid-MAT for a membrane of 128 DPPC and 128 DPPE and a mixed 128 DPPC+128 DPPE+Drug. My atom reference for DPPC is P, so ¿the atom reference for the DPPE need to be necesarili the P too?. Because when i run this, the result value of the area per lipid is the same for the mixed membrane and mixed+drug membrane. Also, i change the atom reference in DPPE for HS16660 and P for DPPC, this according the place occupies by P in DPPC, but the area per lipid is the same for mixed membrane and mixed membrane+drug. How i calculate or know my atom reference in case i have 2 phospholipids in a mixed bilayer?