Thermotropic lipid phase separation in the human immunodeficiency virus.
Biochim Biophys Acta
; 943(2): 331-42, 1988 Aug 18.
Article
em En
| MEDLINE
| ID: mdl-2840961
ABSTRACT
The presence of thermodependent lipid domains in the envelope of the human immunodeficiency virus (HIV) was studied. HIV was propagated in Hut-78 cells and purified by differential-gradient centrifugation. Since the virus was highly infectious in cell culture and Western blots of detergent-inactivated HIV showed envelope proteins when exposed to sera containing anti-HIV antibodies, this viral preparation was not deficient in 'spike' or 'knob' particles. Electron spin resonance (ESR) studies of intact HIV labeled with 5-nitroxide stearate (5-NS) indicated that a temperature-dependent lipid phase separation occurs with a high onset at approx. 42 degrees C and a low onset at approx. 15 degrees C. Cooling below 42 degrees C induces 5-NS clustering. Similar phase separations with high onsets at approx. 37-38 degrees C were previously identified in 5-NS labeled human erythrocytes (cholesterol/phospholipid (C/P) molar ratio = 0.90) and cholesterol-loaded (C/P = 0.85-0.98) rat liver plasma membranes. These were attributed to a temperature-sensitive redistribution of endogenous lipid components such that 5-NS is excluded from cholesterol-rich domains and tends to reside in cholesterol-poor domains at low temperatures. Since HIV has a lipid envelope with a similarly high C/P of 0.88 (Aloia et al. (1988) Proc. Natl. Acad. Sci. USA 85, 900-904), cholesterol-rich and cholesterol-poor domains also probably exist in HIV at physiologic temperatures. The reduced stability and infectivity of HIV noted on heating above 42 degrees C may be due, in part, to the abolition of these thermodependent domains.
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Base de dados:
MEDLINE
Assunto principal:
HIV
/
Temperatura Alta
/
Fluidez de Membrana
/
Lipídeos de Membrana
Limite:
Female
/
Humans
/
Male
Idioma:
En
Revista:
Biochim Biophys Acta
Ano de publicação:
1988
Tipo de documento:
Article