Secretory and viral fusion may share mechanistic events with fusion between curved lipid bilayers.
Proc Natl Acad Sci U S A
; 95(16): 9274-9, 1998 Aug 04.
Article
en En
| MEDLINE
| ID: mdl-9689070
Activation energies for the individual steps of secretory and viral fusion are reported to be large [Oberhauser, A. F., Monck, J. R. & Fernandez, J. M. (1992) Biophys. J. 61, 800-809; Clague, M. J., Schoch, C., Zech, L. & Blumenthal, R. (1990) Biochemistry 29, 1303-1308]. Understanding the cause for these large activation energies is crucial to defining the mechanisms of these two types of biological membrane fusion. We showed recently that the fusion of protein-free model lipid bilayers mimics the sequence of steps observed during secretory and viral fusion, suggesting that these processes may involve common lipid, rather than protein, rearrangements. To test for this possibility, we determined the activation energies for the three steps that we were able to distinguish as contributing to the fusion of protein-free model lipid bilayers. Activation energies for lipid rearrangements associated with formation of the reversible first intermediate, with conversion of this to a semi-stable second intermediate, and with irreversible fusion pore formation were 37 kcal/mol, 27 kcal/mol, and 22 kcal/mol, respectively. The first and last of these were comparable to the activation energies observed for membrane lipid exchange (42 kcal/mol) during viral fusion and for the rate of fusion pore opening during secretory granule release (23 kcal/mol). This striking similarity suggests strongly that the basic molecular processes involved in secretory and viral fusion involve a set of lipid molecule rearrangements that also are involved in model membrane fusion.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Membrana Dobles de Lípidos
/
Fusión de Membrana
Idioma:
En
Revista:
Proc Natl Acad Sci U S A
Año:
1998
Tipo del documento:
Article
País de afiliación:
Estados Unidos
Pais de publicación:
Estados Unidos