The complete Consensus V3 loop peptide of the envelope protein gp120 of HIV-1 shows pronounced helical character in solution.
The disulfide bridge closed cyclic peptide corresponding to the whole Consensus V3 loop of the envelope protein gp120 of HIV-1 was examined by proton 2D-NMR spectroscopy in water and in a 20% trifluoroethanol/water solution. In water, NOE data support a beta-turn conformation for the central conservative GPGR region and point towards partial formation of a helix in the C-terminal part. Upon addition of trifluoroethanol, a C-terminal helix is formed. This is evidenced by NOE data, alpha-proton chemical shift changes and changes in the JN alpha vicinal coupling constants. The C-terminal helix is amphipathic and also occurs in other examined strains. It could therefore be an important feature for the functioning of the V3 loop.
Vranken
W F
WF
Department of Organic Chemistry, University of Gent, Belgium.
Budesinsky
M
M
Fant
F
F
Boulez
K
K
Borremans
F A
FA
D000595:Amino Acid Sequence; D016384:Consensus Sequence; D015699:HIV Envelope Protein gp120 / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry*; D011487:Protein Conformation; D016415:Sequence Alignment; D012996:Solutions; D014270:Trifluoroethanol / Q000737:chemistry; D014867:Water / Q000737:chemistry
D015699:HIV Envelope Protein gp120; C059762:HIV envelope protein gp120 (305-321); D010446:Peptide Fragments; D012996:Solutions; D014867:Water; D014270:Trifluoroethanol