Lysophosphatidylcholine, a major
phospholipid component of
oxidized low-density lipoprotein, is implicated in many inflammatory diseases, including
atherosclerosis. We previously reported that Asp-
hemolysin-related synthetic
peptide (P21) composed of 21
amino acid residues markedly inhibits the bioactivities of
oxidized low-density lipoprotein and
lysophosphatidylcholine, by directly binding to
oxidized low-density lipoprotein and
lysophosphatidylcholine. Here, to clarify whether P21 specifically binds to
lysophosphatidylcholine and what forms of
lysophosphatidylcholine with which P21 interact, we investigated the interaction between P21 containing two
tryptophan residues and
lysophosphatidylcholine by using fluorescence spectroscopy,
polyacrylamide gel electrophoresis, and surface plasmon resonance. From
tryptophan fluorescence measurements, N-terminally biotinylated P21 specifically interacted with
lysophosphatidylcholine, at concentrations exceeding the critical
micelle concentration. From
tryptophan fluorescence quenching, the
tryptophan residues in biotinylated P21 in the presence of
lysophosphatidylcholine were mostly exposed on the outer side of the
peptide. From
polyacrylamide gel electrophoresis and surface plasmon resonance, bound to 1-palmitoyl-lysophosphatidylcholine at concentrations higher than 100 μm, ensuring stable
micelles. These results indicate that biotinylated P21 specifically recognizes
lysophosphatidylcholine micelles. Further study of the interaction between biotinylated P21 and
lysophosphatidylcholine micelles may provide important information for the prevention and treatment for many inflammatory diseases caused by
lysophosphatidylcholine micelles.