Lipid composition-dependent incorporation of multiple membrane proteins into liposomes.
Membrane proteins from bacteria Pasteurella multocida were used as a model for studying its incorporation into liposomes. An important step to achieve efficient high yield protein incorporation in proteoliposomes is the study of the more suitable lipid composition. To this end, we compared the amount of total protein, reconstituted by co-solubilization methods, into liposomes of phospholipids with different polar head groups and acyl chain lengths. The liposomes and proteoliposomes were characterised by isopycnic centrifugation in sucrose gradient and by dynamic light scattering. Experimental and theoretical results were compared considering the effects exerted through the hydrocarbon chain length, volume, and optimal cross-sectional area of the phospholipid (combined in the geometrical critical packing parameter, lipid-protein matching), critical spontaneous radius of curvature of the bilayer vesicle, phase transition temperature of the lipid and ratio of lipid-protein molecules present in the vesicles. The highest incorporation of multiple proteins was found with dipalmitoylphosphatidylcholine (DPPC), reaching a yield of 93% compared to the lower relative amounts incorporated in proteoliposomes of the other lipids. The incorporation of multiple proteins induces a proportional enhancement of vesicular dimension, since DPPC-proteoliposomes have an average diameter of 1850A, compared to the 1430A for pure DPPC vesicles.
Departamento de Química, Faculdade de Filosofia Ciências e Letras de Ribeirão Preto/USP, Avenida Bandeirantes 3900, Ribeirão Preto, SP 14040-901, Brazil.
Katia R P
KR
Daghastanli
Rinaldo B
RB
Ferreira
Geraldo
G
Thedei
Bruno
B
Maggio
Pietro
P
Ciancaglini
D015153:Blotting, Western; D004591:Electrophoresis, Polyacrylamide Gel; D008565:Membrane Proteins / Q000737:chemistry*; D008854:Microscopy, Electron; D010743:Phospholipids / Q000737:chemistry*; D011510:Proteolipids
D008565:Membrane Proteins; D010743:Phospholipids; D011510:Proteolipids; C020485:proteoliposomes