title: Lipid-protein interactions in human plasma LDL evidenced by magnetic resonance.
abstract: Low density lipoprotein (LDL) particles exhibit extremely complex three-dimensional structural organization which is still not understood at the molecular level. The aim of this study was to provide the experimental evidence of a direct non-covalent interaction of the protein part with the lipid matrix. The approach was based on the combination of (1)H NMR (600 MHz) spectroscopy with thiol-specific spin labeling of the protein (apoB). It is shown that the spectral peaks assigned to the methyl head groups of phosphatidylcholine and sphingomyelin in the (1)H spectra of LDL exhibit line broadening when otherwise free thiol groups of apoB are covalently modified by methanethiosulfonate spin label. The effect is similar in the presence of water soluble paramagnetic compound. These results indicate that fragments of apoB, which are part of the receptor binding region, are directly in contact with the solvated phospholipid head groups of the lipid matrix.
authors.affiliation: Ruder Bosković Institute, Zagreb, Croatia. kveder@irb.hr
authors.forename: Marina
authors.initials: M
authors.lastname: Kveder
authors.forename: Zeljko
authors.initials: Z
authors.lastname: Marinić
authors.forename: Anita
authors.initials: A
authors.lastname: Krisko
authors.forename: Drazen
authors.initials: D
authors.lastname: Vikić-Topić
authors.forename: Greta
authors.initials: G
authors.lastname: Pifat
mesh_terms: D001055:Apolipoproteins B / Q000737:chemistry* / Q000378:metabolism; D001665:Binding Sites; D006801:Humans; D008055:Lipids / Q000737:chemistry*; D008077:Lipoproteins, LDL / Q000097:blood / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D010743:Phospholipids / Q000097:blood / Q000737:chemistry; D011506:Proteins / Q000737:chemistry* / Q000378:metabolism; D013113:Spin Labels
chemical_list: D001055:Apolipoproteins B; D008055:Lipids; D008077:Lipoproteins, LDL; D010743:Phospholipids; D011506:Proteins; D013113:Spin Labels