Unveiling a complex phase transition in monolayers of a phospholipid from the annular region of transmembrane proteins.
The lateral packing properties of phospholipids that surround transmembrane proteins are fundamental in the biological activity of these proteins. In this work, Langmuir monolayers of one such lipid, 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine (POPE), are studied with a combination of pressure-area isotherm analysis, Brewster angle microscopy, and atomic force microscopy of extracted films. The analysis reveals a sequence of phase transitions LE-LC-LC' occurring in a narrow packing range. The lateral pressures and area densities of these phases provided meanings for the packing requirements in the annular lipid region of typical transmembrane proteins.
Domènech
Oscar
O
Departament de Química Física, Facultat de Química, Universitat de Barcelona, E-08028 Barcelona, Spain.
Ignés-Mullol
Jordi
J
Montero
M Teresa
MT
Hernandez-Borrell
Jordi
J
D029968:Escherichia coli Proteins / Q000737:chemistry; D008565:Membrane Proteins / Q000737:chemistry*; D008567:Membranes, Artificial; D018625:Microscopy, Atomic Force; D008956:Models, Chemical; D009004:Monosaccharide Transport Proteins / Q000737:chemistry; D044367:Phase Transition; D010714:Phosphatidylethanolamines / Q000737:chemistry*; D010743:Phospholipids / Q000737:chemistry*; D027981:Symporters / Q000737:chemistry
D029968:Escherichia coli Proteins; C050221:LacY protein, E coli; D008565:Membrane Proteins; D008567:Membranes, Artificial; D009004:Monosaccharide Transport Proteins; D010714:Phosphatidylethanolamines; D010743:Phospholipids; D027981:Symporters; C057561:1-palmitoyl-2-oleoylphosphatidylethanolamine