title: NMR study of the peptide present in the principal neutralizing determinant (PND) of HIV-1 envelope glycoprotein gp120.
abstract: The peptide sequence Gly-Pro-Gly-Arg-Ala-Phe (GPGRAF) is present in many principal neutralizing determinants (PND) of the human immunodeficiency virus type-1 (HIV-1). It has been shown that peptides from the PND sequence contain a significant beta turn in the conserved Gly-Pro-Gly-Arg sequence. In order to find out whether or not the smaller subunits also contain this turn, we have studied the NMR of a hexapeptide [GPGPRAF, peptide (I)], a heptapeptide Gly-Pro-Gly-Arg-Ala-Phe-Cys [GPGRAFC, peptide (II)] and a dodecapeptide [GPGRAFGPGRAF, peptide (III)], retaining the side chain protecting groups. Although the majority of conformations for these peptides are disordered, there is a considerable propensity of structures with beta turn in the GPGR sequence. While peptide (I) and peptide (III) seem to have both type I and type II beta turn conformations, peptide (II) shows a propensity of only type II beta turn. The nascent structures obtained in these peptides may get stabilized as the receptor binding conformation in the presence of the receptors, thus playing a significant role in vaccine development against HIV.
authors.affiliation: Indian Institute of Chemical Technology, Hyderabad, India.
authors.forename: A V
authors.initials: AV
authors.lastname: Sarma
authors.forename: T V
authors.initials: TV
authors.lastname: Raju
authors.forename: A C
authors.initials: AC
authors.lastname: Kunwar
mesh_terms: D015699:HIV Envelope Protein gp120 / Q000737:chemistry*; D015497:HIV-1 / Q000737:chemistry*; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D010449:Peptide Mapping; D010455:Peptides / Q000737:chemistry; D011487:Protein Conformation
chemical_list: D015699:HIV Envelope Protein gp120; D010455:Peptides