       Document 0843
 DOCN  M9640843
 TI    Structural study of the interaction between the SIV fusion peptide and
       model membranes.
 DT    9604
 AU    Colotto A; Martin I; Ruysschaert JM; Sen A; Hui SW; Epand RM; Department
       of Biochemistry, McMaster University, Hamilton,; Ontario, Canada.
 SO    Biochemistry. 1996 Jan 23;35(3):980-9. Unique Identifier : AIDSLINE
       MED/96146434
 AB    It has been shown that there is a correlation between the fusogenecity
       of synthetic peptides corresponding to the N-terminal segment of
       wild-type and mutant forms of simian immunodeficiency virus gp32 (SIV)
       and their mode of insertion into lipid bilayers. Fusogenic activity is
       only observed when the peptide inserts into the bilayer with an oblique
       orientation. Since bilayer destabilization is a necessary step in
       membrane fusion, we investigate how fusion peptides, which insert at
       different orientations into lipid bilayers, structurally affect model
       membranes. We use X-ray diffraction to investigate the structural
       effects of two synthetic peptides on three different lipid systems. One
       peptide corresponds to the wild-type sequence (SIVwt), which inserts
       into the membrane at an oblique angle and is fusogenic. The other
       peptide has a rearranged sequence (SIVmutV), inserts into the membrane
       along the bilayer normal, and is nonfusogenic. Our results are expressed
       through different structural effects, which depend on the lipid system:
       for example, (i) disordering of the L alpha phase as evidenced by the
       broadening of the diffraction peaks, (ii) morphological convertion of
       multilamellar vesicles into unilamellar vesicles, (iii) decrease of the
       hexagonal phase cell parameter when SIVwt is added, and (iv) change in
       the conditions for the formation of cubic phases as well as its kinetic
       stability over a range of temperatures. Some of these observations are
       explicable based on the fact that the SIVwt destabilizes bilayers by
       inducing a negative monolayer curvature, while the SIVmutV destabilizes
       bilayers by inducing a positive monolayer curvature. Finally, we present
       a model which describes how these findings correlate with fusogenic
       activity and fusion inhibitory activity, respectively.
 DE    Amino Acid Sequence  Lipid Bilayers/*CHEMISTRY  Molecular Sequence Data
       Support, Non-U.S. Gov't  SIV/*CHEMISTRY  Viral Fusion
       Proteins/*CHEMISTRY  X-Ray Diffraction  JOURNAL ARTICLE

       SOURCE: National Library of Medicine.  NOTICE: This material may be
       protected by Copyright Law (Title 17, U.S.Code).

