Loss of apoB-100 secondary structure and conformation in hydroperoxide rich, electronegative LDL(-).
Free Radic Biol Med
; 31(1): 82-9, 2001 Jul 01.
Article
en En
| MEDLINE
| ID: mdl-11425493
A subpopulation of low-density lipoproteins (LDL) is present in human plasma that contains lipid hydroperoxides and is more negatively charged (LDL(-)) than normal native LDL. By circular dichroism and tryptophan lifetime measurements we found that apoB-100 secondary structure is markedly decreased and its conformation is severely altered in LDL(-). The low tryptophan fluorescence intensity confirms the oxidative degradation of the lipoprotein, and the very long lifetime value of one of its decay components indicates a low polarity environment for the remaining unbleached residues. Either a peculiar folding or, most likely, a sinking of the apoB-100 into the lipid core can account for the observed long lifetime component. Oxidation in vitro produces a similar unfolding of the apolipoprotein but the lifetime of tryptophan fluorescence is shifted to lower values, indicating that the denatured apoprotein remains at the hydrophilic surface of the lipoprotein particle. A disordering and an increased polarity of the LDL(-) surface lipids was demonstrated by measuring the generalized polarization of 2-dimethylamino-6-lauroylnaphthalene (Laurdan). The looser monolayer packing apparently favors the new conformation of apoB-100 and its sinking into a more hydrophobic environment, possibly accounting for it reduced receptor binding properties.
Buscar en Google
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Apolipoproteínas B
/
Lipoproteínas LDL
/
2-Naftilamina
Límite:
Adult
/
Humans
Idioma:
En
Revista:
Free Radic Biol Med
Asunto de la revista:
BIOQUIMICA
/
MEDICINA
Año:
2001
Tipo del documento:
Article
País de afiliación:
Italia
Pais de publicación:
Estados Unidos