Abstract:
:Experiments have shown that the ability of the HIV-1 virus to infect cells can be greatly diminished by deactivation of the N-terminal (fusion) peptide of its glycoprotein gp41. Deactivation can be achieved by the deletion of several amino acid residues, or replacement of a hydrophobic residue with a polar residue, to form mutant variants of the wild-type peptide. We report Monte Carlo simulation studies of a simplified peptide/membrane model, representing the interaction of an HIV-1 fusion peptide (FP) and four closely related mutagens with a lipid bilayer. In agreement with experimental results, we show that FP inserts deeply into the bilayer at approximately 40 degrees to the bilayer normal. We also show a previously unreported behavior of membrane peptides, namely their equilibrium partitioning between several distinct conformations within the bilayer. We quantify this partitioning behavior and characterize each conformation in terms of its geometry, energy, and entropy. The diminished ability of FP mutagens to hemolyse and aggregate red blood cells due to their partitioning into unfavorable conformations, is also discussed. Our analysis supports a negative curvature mechanism for red blood cell hemolysis by FP. We also suggest that the small repulsive forces between surface-adsorbed peptides in opposing membrane surfaces may block aggregation.
journal_name
Biophys Jjournal_title
Biophysical journalauthors
Maddox MW,Longo MLdoi
10.1016/S0006-3495(02)75313-7subject
Has Abstractpub_date
2002-12-01 00:00:00pages
3088-96issue
6eissn
0006-3495issn
1542-0086pii
S0006-3495(02)75313-7journal_volume
83pub_type
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