Hexagonal arrangement of phospholipids in bilayer membranes<xref rid="cpb_29_3_030505fn1" ref-type="fn">*</xref><fn id="cpb_29_3_030505fn1"><label>*</label><p>Project supported by the National Natural Science Foundation of China (Grant No. 11904231), the National Key R&D Program of China (Grant Nos. 2018YFE0205501 and 2018YFB1801500), and Shanghai Sailing Program, China (Grant No. 19YF1434100).</p></fn>

Hexagonal arrangement of phospholipids in bilayer membranes**

Project supported by the National Natural Science Foundation of China (Grant No. 11904231), the National Key R&D Program of China (Grant Nos. 2018YFE0205501 and 2018YFB1801500), and Shanghai Sailing Program, China (Grant No. 19YF1434100).

Chen Xiao-Wei, Yuan Ming-Xia, Guo Han, Zhu Zhi^‡

Free energy landscape of lipid molecule in bilayer. (a) Landscape of the free energy fluctuation (F) around a DMPC molecule with respect to parameters r_X and r_Y. The red and blue colors correspond to the free energy fluctuation with lower and higher values, respectively. The unit of free energy fluctuation is kJ/mol. The solid and dashed hexagons represent the nearest and second neighbor regions of a DMPC molecule, respectively. (b) 3-dimensional arrangement sketch of lipids in bilayer membrane, where a cylindrical lipid molecule consists of a red ball and two gray curves.