ISSN:
1573-3904
Keywords:
Conformational switching
;
Membrane fusion
;
Peptide conformation
;
Peptide-lipid interaction
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
Notes:
Abstract The human immunodeficiency virus type-1 (HIV-1) fusionpeptide, corresponding to a sequence of 23 amino acidresidues at the N-terminus of the spike transmembranesubunit gp41, has the capacity to destabilizenegatively charged and neutral large unilamellarvesicles, representing, respectively, the acidic andthe neutral fraction of the plasma membrane lipids ofviral target cells. As revealed by infraredspectroscopy, the peptide associated with the vesiclesmay exist in different conformations. In negativelycharged membranes the structure is mainly anα-helix, while in Ca2+-neutralizednegatively charged membranes the conformation switchesto a predominantly extended conformation. In membranescomposed of zwitterionic phospholipids andcholesterol, the peptide also adopts a predominantextended structure. The α-helical structurepermeabilizes negatively charged vesicles but does notinduce membrane fusion. The peptide in β-typeconformation, on the other hand, permeabilizes neutralmembranes and triggers fusion. As seen by31P NMR, the latter structure also exhibits thecapacity to alter the lamellar organization of the membrane.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1008869409753
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