title: Conformational features of a synthetic cyclic peptide corresponding to the complete V3 loop of the RF HIV-1 strain in water and water/trifluoroethanol solutions.
abstract: The disulfide-bridge-closed cyclic peptide corresponding to the whole V3 loop of the RF HIV-1 strain was examined by proton two-dimensional NMR spectroscopy in water and water/trifluoroethanol solutions. Although most of the peptide is conformationally averaged in water, the NOE data support a beta-turn conformation for the central conservative GPGR region and the presence of nascent helix. Upon addition of trifluoroethanol, helix formation in the C-terminal part becomes apparent. This is confirmed by CD data. NOEs indicative of multiple and transient beta-turns around the Asn6 glycosylation site and NOEs fitting X-ray data on a linear V3 peptide-Fab complex also emerge. The C-terminal helix is shown to have amphipathic character and might thus assist in the infection process.
authors.affiliation: Department of Organic Chemistry, University of Gent, Belgium.
authors.forename: W F
authors.initials: WF
authors.lastname: Vranken
authors.forename: M
authors.initials: M
authors.lastname: Budesinsky
authors.forename: J C
authors.initials: JC
authors.lastname: Martins
authors.forename: F
authors.initials: F
authors.lastname: Fant
authors.forename: K
authors.initials: K
authors.lastname: Boulez
authors.forename: H
authors.initials: H
authors.lastname: Gras-Masse
authors.forename: F A
authors.initials: FA
authors.lastname: Borremans
mesh_terms: D000595:Amino Acid Sequence; D002942:Circular Dichroism; D015699:HIV Envelope Protein gp120 / Q000737:chemistry*; D015497:HIV-1 / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry*; D010456:Peptides, Cyclic / Q000737:chemistry*; D011487:Protein Conformation; D012996:Solutions; D014270:Trifluoroethanol; D014867:Water
chemical_list: D015699:HIV Envelope Protein gp120; D010446:Peptide Fragments; D010456:Peptides, Cyclic; D012996:Solutions; D014867:Water; D014270:Trifluoroethanol