Document 0859
 DOCN  M9590859
 TI    Effect of the conformation of a peptide from gp41 on binding and domain
       formation in model membranes.
 DT    9509
 AU    Koenig BW; Bergelson LD; Gawrisch K; Ward J; Ferretti JA; Laboratory of
       Biophysical Chemistry, NHLBI, NIH, Bethesda, MD; 20892-0380, USA.
 SO    Mol Membr Biol. 1995 Jan-Mar;12(1):77-82. Unique Identifier : AIDSLINE
       MED/95284892
 AB    Binding of the peptide fragment 828-848 (P828), amino acid sequence
       RVIEVVQGACRAIRHIPRRIR, from the carboxy-terminal region of the envelope
       glycoprotein gp41 of human immunodeficiency virus type 1 (HIV-1) to
       membranes composed of a mixture of neutral and negatively charged
       phospholipids results in domain or cluster formation of the charged
       lipid. The conformation and dynamics of the peptide are investigated in
       solution and in the presence of sodium dodecyl sulphate (SDS) micelles
       using high resolution nuclear magnetic resonance (NMR) spectroscopy and
       circular dichroism (CD) spectropolarimetry. The CD results demonstrate
       that addition of either SDS, negatively charged phospholipid liposomes,
       or trifluoroethanol (TFE) induces a conformational transition of the
       peptide from a random coil or an extended chain in water to a more
       ordered structure with an estimated helical content of up to 60%. The
       structure of the peptide in a membrane mimetic SDS solution was
       investigated in detail using two-dimensional NMR. The measurements
       demonstrate the existence of a helical component in the peptide
       conformation in the SDS-bound state. The peptide most likely exists as
       an ensemble of conformations with exchange times between them which are
       fast on the chemical shift NMR time scale (10(-3) s). Simple
       neutralization of the six arginine sidechain charges does not cause the
       peptide to adopt an ordered structure. Thus, there is an additional
       requirement for the structural transition such as that resulting from
       constraint of the peptide on a surface, or localization of the peptide
       at the lipid-water interface where the polarity is lower.(ABSTRACT
       TRUNCATED AT 250 WORDS)
 DE    Amino Acid Sequence  Circular Dichroism  Gene Products,
       env/*CHEMISTRY/*METABOLISM  Human  HIV Envelope Protein
       gp41/*CHEMISTRY/*METABOLISM  Lipid Bilayers  Membrane
       Lipids/*CHEMISTRY/*METABOLISM  *Models, Biological  Molecular Sequence
       Data  Nuclear Magnetic Resonance/METHODS  Peptide
       Fragments/*CHEMISTRY/*METABOLISM  Protein Structure, Secondary  Support,
       Non-U.S. Gov't  Surface Properties  JOURNAL ARTICLE

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