Phosphatidylserine headgroup diastereomers translocate equivalently across human erythrocyte membranes.
The natural chiral phospholipid substrates for the plasma membrane aminophospholipid translocator are L-alpha-phosphatidyl-L-serine and L-alpha-phosphatidylethanolamine. The glyceric D-stereoisomers of these lipids, D-alpha-phosphatidyl-L-serine and D-alpha-phosphatidylethanolamine, are not translocated (Martin, O.C. and Pagano, R.E. (1987) J. Biol. Chem. 262, 5890-5898). We have synthesized a diastereomer of phosphatidylserine, L-alpha-phosphatidyl-D-serine, to study the effects of headgroup stereochemistry on translocation. The diastereomer was synthesized as the dilauroyl (12:0) species, and the translocation was monitored by human erythrocyte morphology changes at 25 degrees C and 37 degrees C. Unlike other phosphatidylserine stereoisomers, L-alpha-phosphatidyl-D-serine is translocated to the same degree as the natural L,L-isomer. Incorporation of apparently equal amounts of the L,D- and L,L-diastereomers does produce minor quantitative differences in the cell morphological response, possibly as a result of differences in lipid packing of the two isomers.
Hall
M P
MP
Department of Chemistry, Stanford University, CA 94305-5080.
Huestis
W H
WH
D004910:Erythrocyte Membrane / Q000378:metabolism* / Q000648:ultrastructure; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D010713:Phosphatidylcholines; D010718:Phosphatidylserines / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D013237:Stereoisomerism; D013696:Temperature
D010713:Phosphatidylcholines; D010718:Phosphatidylserines; C055534:dilauroylphosphatidylserine; C017251:1,2-oleoylphosphatidylcholine