Assessment of Key Amino-Acid Residues of CD36 in Specific Binding Interaction with an Oxidized Low-Density Lipoprotein

2013 ◽  
Vol 77 (5) ◽  
pp. 1134-1137 ◽  
Author(s):  
Marie TAKAI ◽  
Satoshi TSUZUKI ◽  
Yukari MATSUNO ◽  
Yuki KOZAI ◽  
Ai EGUCHI ◽  
...  
Keyword(s):  
Amino Acid ◽  
Specific Binding ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Low Density ◽  
Amino Acid Residues ◽  
Oxidized Low Density Lipoprotein ◽  
Binding Interaction

Binding and Uptake of 125Iodine-Labelled, Oxidized Low Density Lipoprotein by Macrophages: Comparism of the Effects of a-Tocopherol, Probucol, Pyridoxal-5'-phosphate and Magnesium-pyridoxal-5'-phosphate-glutamate

1997 ◽  
Vol 52 (1-2) ◽  
pp. 97-104 ◽  
Author(s):  
Daniela Selmer ◽  
Reingard Senekowitsch-Schmidtke ◽  
W. Schneider ◽  
E. F. Elstner
Keyword(s):  
Specific Binding ◽  
Low Density Lipoprotein ◽  
Scavenger Receptor ◽  
Density Lipoprotein ◽  
Low Density ◽  
Protective Effects ◽  
Oxidized Low Density Lipoprotein ◽  
Unspecific Binding

Abstract Specific and unspecific binding and uptake (internalization) by macrophages of 125iodine -labelled, copper-oxidized human low density lipoprotein is differently influenced by the anti­ oxidants α-tocopherol (α-Toc), probucol (Prob), pyridoxal-5'-phosphate (PP) and the magnesium-pyridoxal-5'-phosphate glutamate complex (MPPG). Binding as well as internalization, mediated by the so-called "scavenger receptor" is lower in the presence of MPPG whereas both specific binding and internalization are enhanced. The comparison of the effects in vitro allows a rating of the potentially anti-atherogenic and thus protective effects of the tested substances as follows: MPPG > PP > α-Toc > Prob.

Conserved C-terminal residues within the lectin-like domain of LOX-1 are essential for oxidized low-density-lipoprotein binding

2001 ◽  
Vol 355 (2) ◽  
pp. 289-296 ◽  
Author(s):  
Mingyi CHEN ◽  
Shuh NARUMIYA ◽  
Tomoh MASAKI ◽  
Tatsuya SAWAMURA
Keyword(s):  
Amino Acid ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Basic Amino Acid ◽  
Binding Activity ◽  
Functional Domain ◽  
Low Density ◽  
Oxidized Low Density Lipoprotein ◽  
Specific Domain ◽  
Lectin Domain

Lectin-like oxidized low-density-lipoprotein (oxLDL) receptor-1 (LOX-1) is a cell-surface endocytosis receptor for atherogenic oxLDL, which is highly expressed in endothelial cells. Recent studies suggest that it may play significant roles in atherogenesis. LOX-1 is a type-II membrane protein that structurally belongs to the C-type lectin family molecules. This study was designed to characterize the specific domain on LOX-1 that recognizes oxLDL. Truncation of the lectin domain of LOX-1 abrogated oxLDL-binding activity. Deletion of the utmost C-terminal ten amino acid residues (261-270) was enough to disrupt the oxLDL-binding activity. Substitutions of Lys-262 and/or Lys-263 with Ala additively attenuated the activity. Serial-deletion analysis showed that residues up to 265 are required for the expression of minimal binding activity, although deletion of the C-terminal three residues (268-270) still retained full binding activity. Consistently, these alterations in LOX-1 impaired the recognition by a functionally blocking monoclonal antibody for LOX-1. These data demonstrated the distinct role of the lectin domain as the functional domain recognizing LOX-1 ligand. The conserved C-terminal residues of lectin-like domain are essential for binding oxLDL. Particularly, the basic amino acid pair is important for the binding.

scholarly journals Reduction of Cu(II) by lipid hydroperoxides: implications for the copper-dependent oxidation of low-density lipoprotein

1997 ◽  
Vol 322 (2) ◽  
pp. 425-433 ◽  
Author(s):  
Rakesh P. PATEL ◽  
Dimitri SVISTUNENKO ◽  
Michael T. WILSON ◽  
Victor M. DARLEY-USMAR
Keyword(s):  
Lipid Peroxidation ◽  
Amino Acid ◽  
Unsaturated Fatty Acids ◽  
Low Density Lipoprotein ◽  
Biological Significance ◽  
Density Lipoprotein ◽  
Peroxyl Radicals ◽  
Lipid Hydroperoxides ◽  
Low Density ◽  
Amino Acid Residues

The Cu(II)-promoted oxidation of lipids is a lipid hydroperoxide (LOOH)-dependent process that has been used routinely to assess the oxidizability of low-density lipoprotein (LDL) in human subjects. Metal-dependent redox reactions, including those mediated by copper, have been implicated in the pathogenesis of atherosclerosis. Despite its widespread use and possible biological significance, key elements of the mechanism are not clear. For example, although it is evident that copper acts as a catalyst, which implies a redox cycle between the Cu(II) and Cu(I) redox states, the reductants remain uncertain. In LDL these could include α-tocopherol, amino acid residues on the protein and LOOH. However, both α-tocopherol and amino acid residues are probably consumed before the most rapid phase of lipid peroxidation occurs, suggesting that another reductant must be donating electrons to Cu(II), the most likely candidate being LOOH. This role has been disputed, since LDLs nominally devoid of LOOH are still capable of reducing Cu(II) to Cu(I) and thermodynamic calculations for this reaction are not favourable. Direct investigation of the role of LOOH as reductant has not been reported and in the present study, using simple lipid systems and LDL, we have re-examined this issue using the Cu(I) chelator bathocuproine. We have shown that Cu(II) may promote lipid peroxidation in liposomes, which do not contain either protein or α-tocopherol, and that this is associated with reduction to Cu(I). The data also indicate that an equilibrium between free Cu(II) and LOOH exists, which only in the presence of an oxidizable substrate, i.e. unsaturated fatty acids, is shifted towards formation of Cu(I) and lipid-derived peroxyl radicals. We propose that reduction of Cu(II) by LOOH is a necessary component in sustaining the propagation of lipid peroxidation and that the formation of peroxyl radicals and their products in a lipid environment is sufficient to overcome thermodynamic barriers to the reaction.

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