A novel oxidized low-density lipoprotein-binding protein, Asp-hemolysin, recognizes lysophosphatidylcholine.
Oxidized low-density lipoprotein (Ox-LDL) plays an important role in the initiation and progression of atherosclerosis. Asp-hemolysin, a hemolytic toxin from Aspergillus fumigatus, is a specific, high affinity binding protein for Ox-LDL. We have previously shown that Ox-LDL strongly inhibits the hemolytic activity of Asp-hemolysin, and that the removal of lysophosphatidylcholine (lysoPC) from Ox-LDL abolished the inhibition. In the present study, to clarify the binding mechanism of Asp-hemolysin to Ox-LDL, we investigated the interaction between Asp-hemolysin and lysoPC as a typical lipid moiety of Ox-LDL. Based on western blot analysis, the binding of Asp-hemolysin to LDL, oxidized for different times, depended on the lysoPC content in each Ox-LDL. In addition, the inhibition of lysoPC production in Ox-LDL by phenylmethylsulfonyl fluoride (PMSF) pretreatment of LDL resulted in a marked decrease of Asp-hemolysin binding to PMSF-pretreated Ox-LDL. Furthermore, the binding analysis of Asp-hemolysin to lysoPC using ion-exchange chromatography revealed that Asp-hemolysin directly binds to lysoPC.
Kudo
Yoichi
Y
Hygiene Research Laboratory, Sendai Hospital of East Japan Railway Company, Sendai.
Ootani
Toshihiro
T
Kumagai
Takeshi
T
Fukuchi
Yuji
Y
Ebin
Keiichi
K
Yokota
Katsushi
K
D015153:Blotting, Western; D002852:Chromatography, Ion Exchange; D005656:Fungal Proteins / Q000302:isolation & purification / Q000494:pharmacology*; D006460:Hemolysin Proteins / Q000302:isolation & purification / Q000494:pharmacology*; D006801:Humans; D008077:Lipoproteins, LDL / Q000378:metabolism*; D008244:Lysophosphatidylcholines / Q000737:chemistry*; D010084:Oxidation-Reduction; D010664:Phenylmethylsulfonyl Fluoride / Q000494:pharmacology; D011480:Protease Inhibitors / Q000494:pharmacology; D011485:Protein Binding; D017392:Thiobarbituric Acid Reactive Substances
C089497:Asp-HS protein, Aspergillus fumigatus; D005656:Fungal Proteins; D006460:Hemolysin Proteins; D008077:Lipoproteins, LDL; D008244:Lysophosphatidylcholines; D011480:Protease Inhibitors; D017392:Thiobarbituric Acid Reactive Substances; D010664:Phenylmethylsulfonyl Fluoride