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Titolo:
Apolipoprotein A-I localization and dipalmitoylphosphatidylcholine dynamics in reconstituted high density lipoproteins
Autore:
Dergunov, AD; Dobretsov, GE;
Indirizzi:
Natl Res Ctr Prevent Med, Moscow 101953, Russia Natl Res Ctr Prevent Med Moscow Russia 101953 Med, Moscow 101953, Russia Res Inst Phys Chem Med, Moscow 119828, Russia Res Inst Phys Chem Med Moscow Russia 119828 m Med, Moscow 119828, Russia
Titolo Testata:
CHEMISTRY AND PHYSICS OF LIPIDS
fascicolo: 2, volume: 104, anno: 2000,
pagine: 161 - 173
SICI:
0009-3084(200002)104:2<161:AALADD>2.0.ZU;2-5
Fonte:
ISI
Lingua:
ENG
Soggetto:
RESOLUTION OPTICAL SPECTROSCOPY; TRANS-PARINARIC ACID; POLYENE FATTY-ACIDS; FLUORESCENT-PROBES; LIPID PHASES; CHOLESTEROL; MEMBRANES; PROTEIN; RECOMBINANTS; COMPLEXES;
Keywords:
apolipoprotein A-I; high density lipoproteins; molecular dynamics; non-radiative energy transfer; protein-lipid interactions; reconstituted HDL;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
37
Recensione:
Indirizzi per estratti:
Indirizzo: Dergunov, AD Natl Res Ctr Prevent Med, 10 Petroverigsky St, Moscow 101953,Russia Natl Res Ctr Prevent Med 10 Petroverigsky St Moscow Russia 101953
Citazione:
A.D. Dergunov e G.E. Dobretsov, "Apolipoprotein A-I localization and dipalmitoylphosphatidylcholine dynamics in reconstituted high density lipoproteins", CHEM PHYS L, 104(2), 2000, pp. 161-173

Abstract

The structure and molecular dynamics of recombinant high density lipoproteins (rHDL) were studied by non-radiative energy transfer (NRET), fluorescence anisotropy and intensity measurements. The rHDL particles contained human plasma apolipoprotein (apo) A-I and dipalmitoylphosphatidylcholine (DPPC). Fluorescent cis- and trans-parinaric acids were used both as probes of molecular motion in the particle lipid phase and as accepters in the Forster's energy transfer from ape A-I tryptophan residues to determine particle dimensions, apolipoprotein localization and lipid dynamics. The probes are sensitive to thermal wobbling (macromobility) and conformational deformations(micromobility) of phospholipid acyl chains. The experimental data fitted to various models of the particle structure are compatible with the following: (a) at T<T-t the particles appeared as lens-like discs with a radius ofthe lipid phase of 5 nm and a mean thickness of 4 nm, the value being moreby 20% in the particle centre, the alpha-helices of about 1 nm thickness were located around the edge of the lipid core. Compared to liposomes, both macro- and micromobility of DPPC molecules in rHDL were more rapid due to asignificant disorder of the boundary lipid molecules close to the apo A-I molecule. This disorder led to the increase of the specific surface area per one lipid molecule, S-o. The lipid phase can be divided into three regions: (i) zone I of the most tightly packed lipid (0-1.7 nm from the disc axis) with a S-o value small as 0.5 nm(2); (ii) intermediate zone II (from 1.7 to 4.0 nm); and (iii) boundary lipid zone III (4-5 nm) of significantly disordered lipid with a S-o value large as 0.65 nm(2). (b) at T>T-t the S-o heterogeneity disappeared, the radius of the lipid phase did not increase significantly, not exceeding 5.2-5.4 nm, but protein-induced immobilization oflipid molecules which affected about half or more of the total lipid, became remarkable. The overall effect was the suppression of the transition amplitude in rHDL compared to liposomes. The structural inhomogeneity might underlie the function of the native plasma HDL as the key component of the transport and metabolism of plasma lipids. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.

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Documento generato il 09/04/20 alle ore 00:17:01