Anionic lipids / phospholipids have been implicated also in the structure / function of K + channels, despite crystallographic diacyl-glycerol (dga) being the first and most detected lipid (i.e., 1k4c). This and/or other lipid fragment(s) detected in crystallographic structures occupy four surface shallowgrooves outside of the annular centre of the homotetramer. Interactions of lipid hydrophilic heads with arginine residues from two contiguous monomers ( 64 R and 89 R) are most probably implicated in the crystallographically detected interactions . It may be possible that specific lipids could optimize KcsA channel assembly and/or function , since for instance, KcsA binds phosphatidylglycerol better than phosphatidylcholine . Briefly, four anionic lipids bind KcsA at the four interfaces of each of two adjacent KcsA monomers in surface shallow-grooves per monomer (Figure , red spheres), suggesting that lipid hydrophilic heads and/or their alkyl-chains may allosterically influence K + flows.