The principal neutralizing determinant of HIV-1 located in V3 of gp120 forms a 12-residue loop by internal hydrophobic interactions.
The interactions of the peptide RP135a (RKSI-RIQRGPGRAFVT), corresponding to residues 311-326 of gp120 of HIV-1IIIB, with the anti-gp120 HIV-1IIIB neutralizing antibody 0.5 beta were studied by NMR. The NOESY difference spectra measured using specifically deuterated derivatives of the peptide show exclusively the interactions of the deuterated residues both within the bound peptide and with the Fab fragment of the antibody. These measurements reveal hydrophobic interactions within the bound peptide between Ile-4, Ile-6 and Val-15 that create a 12-residue loop with these residues at the base and the conserved GPGR sequence at its top.
Zvi
A
A
Department of Structural Biology, Weizmann Institute of Science, Rehovot, Israel.
Kustanovich
I
I
Hayek
Y
Y
Matsushita
S
S
Anglister
J
J
D000595:Amino Acid Sequence; D000939:Epitopes / Q000737:chemistry*; D015483:HIV Antibodies / Q000378:metabolism; D015699:HIV Envelope Protein gp120 / Q000737:chemistry* / Q000378:metabolism; D015497:HIV-1 / Q000737:chemistry*; D006801:Humans; D007140:Immunoglobulin Fab Fragments / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D009500:Neutralization Tests; D010446:Peptide Fragments / Q000737:chemistry* / Q000378:metabolism; D011487:Protein Conformation
D000939:Epitopes; D015483:HIV Antibodies; D015699:HIV Envelope Protein gp120; C059762:HIV envelope protein gp120 (305-321); D007140:Immunoglobulin Fab Fragments; D010446:Peptide Fragments