Evidence for a Central Apolipoprotein A-I Domain Loosely Bound to Lipids in Discoidal Lipoproteins That Is Capable of Penetrating the Bilayer of Phospholipid Vesicles

Previous evidence indicated that discoidal reconstituted high density lipoproteins (rHDL) of apolipoprotein A-I (apoA-I) can interact with lipid membranes (Tricerri, M. A., Córsico, B., Toledo, J. D., Garda, H. A., and Brenner, R. R. (1998) <i>Biochim. Biophys. Acta</i> 1391, 67-78). Wit...

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Detalles Bibliográficos
Autores principales:	Córsico, Betina, Toledo, Juan Domingo, Garda, Horacio Alberto
Formato:	Articulo
Lenguaje:	Inglés
Publicado:	2001
Materias:	Ciencias Médicas Apolipoprotein lipid membranes cholesterol exchange
Acceso en línea:	http://sedici.unlp.edu.ar/handle/10915/84699
Aporte de:	SEDICI (UNLP) de Universidad Nacional de La Plata

id	I19-R120-10915-84699
record_format	dspace
institution	Universidad Nacional de La Plata
institution_str	I-19
repository_str	R-120
collection	SEDICI (UNLP)
language	Inglés
topic	Ciencias Médicas Apolipoprotein lipid membranes cholesterol exchange
spellingShingle	Ciencias Médicas Apolipoprotein lipid membranes cholesterol exchange Córsico, Betina Toledo, Juan Domingo Garda, Horacio Alberto Evidence for a Central Apolipoprotein A-I Domain Loosely Bound to Lipids in Discoidal Lipoproteins That Is Capable of Penetrating the Bilayer of Phospholipid Vesicles
topic_facet	Ciencias Médicas Apolipoprotein lipid membranes cholesterol exchange
description	Previous evidence indicated that discoidal reconstituted high density lipoproteins (rHDL) of apolipoprotein A-I (apoA-I) can interact with lipid membranes (Tricerri, M. A., Córsico, B., Toledo, J. D., Garda, H. A., and Brenner, R. R. (1998) <i>Biochim. Biophys. Acta</i> 1391, 67-78). With the aim of studying this interaction, photoactivable reagents and protein cleavage with CNBr and hydroxylamine were used. The generic hydrophobic reagent 3-(trifluoromethyl)-3-(<i>m</i>-[<SUP>125</SUP>I]iodophenyl)diazirine gave information on the apoA-I regions in contact with the lipid phase in the rHDL discs. Two protein regions loosely bound to lipids were detected: a C-terminal domain and a central one located between residues 87 and 112. They consist of class Y amphipathic α-helices that have a different distribution of the charged residues in their polar faces by comparison with class A helices, which predominate in the rest of the apoA-I molecule. The phospholipid analog 1-<i>O</i>-hexadecanoyl-2-<i>O</i>-[9-[[[2-[<SUP>125</SUP>I]iodo-4-(trifluoro-methyl-3-H-diazirin-3-yl)benzyl]oxy]carbonyl-] nonanoyl]-<i>sn</i>-glycero-3-phosphocholine, which does not undergo significant exchange between membranes and lipoproteins, was used to identify the apoA-I domain directly involved in the interaction of rHDL discs with membranes. By incubating either rHDL or lipid-free apoA-I with lipid vesicles containing <SUP>125</SUP>I-TID-PC, only the 87-112 apoA-I segment becomes labeled after photoactivation. These results indicate that the central domain formed by two type Y helices swings away from lipid contact in the discoidal lipoproteins and is able to insert into membrane bilayers, a process that may be of great importance for the mechanism of cholesterol exchange between high density lipoproteins and cell membranes.
format	Articulo Articulo
author	Córsico, Betina Toledo, Juan Domingo Garda, Horacio Alberto
author_facet	Córsico, Betina Toledo, Juan Domingo Garda, Horacio Alberto
author_sort	Córsico, Betina
title	Evidence for a Central Apolipoprotein A-I Domain Loosely Bound to Lipids in Discoidal Lipoproteins That Is Capable of Penetrating the Bilayer of Phospholipid Vesicles
title_short	Evidence for a Central Apolipoprotein A-I Domain Loosely Bound to Lipids in Discoidal Lipoproteins That Is Capable of Penetrating the Bilayer of Phospholipid Vesicles
title_full	Evidence for a Central Apolipoprotein A-I Domain Loosely Bound to Lipids in Discoidal Lipoproteins That Is Capable of Penetrating the Bilayer of Phospholipid Vesicles
title_fullStr	Evidence for a Central Apolipoprotein A-I Domain Loosely Bound to Lipids in Discoidal Lipoproteins That Is Capable of Penetrating the Bilayer of Phospholipid Vesicles
title_full_unstemmed	Evidence for a Central Apolipoprotein A-I Domain Loosely Bound to Lipids in Discoidal Lipoproteins That Is Capable of Penetrating the Bilayer of Phospholipid Vesicles
title_sort	evidence for a central apolipoprotein a-i domain loosely bound to lipids in discoidal lipoproteins that is capable of penetrating the bilayer of phospholipid vesicles
publishDate	2001
url	http://sedici.unlp.edu.ar/handle/10915/84699
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Evidence for a Central Apolipoprotein A-I Domain Loosely Bound to Lipids in Discoidal Lipoproteins That Is Capable of Penetrating the Bilayer of Phospholipid Vesicles

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