A cis proline turn linking two beta-hairpin strands in the solution structure of an antibody-bound HIV-1IIIB V3 peptide.
The refined solution structure of an 18-residue HIV-1IIIB V3 peptide in complex with the Fv fragment of an anti-gp120 antibody reveals an unexpected type VI beta-turn comprising residues RGPG at the center of a beta-hairpin. The central glycine and proline of this turn are linked by a cis peptide bond. The residues of the turn interact extensively with the antibody Fv. 15N[1H] NOE measurements show that the backbone of the peptide, including the central QRGPGR loop, is well ordered in the complex. The solution structure is significantly different from the X-ray structures of HIV-1MN V3 peptides bound to anti-peptide antibodies. These differences could be due to a two-residue (QR) insertion preceding the GPGR sequence in the HIV-1IIIB strain, and the much longer peptide epitope immobilized by the anti-gp120 antibody.
Tugarinov
V
V
Department of Structural Biology, The Weizmann Institute of Science, Rehovot, Israel.
Zvi
A
A
Levy
R
R
Anglister
J
J
D000595:Amino Acid Sequence; D002247:Carbon Isotopes; D015483:HIV Antibodies / Q000737:chemistry* / Q000378:metabolism*; D015699:HIV Envelope Protein gp120 / Q000737:chemistry* / Q000276:immunology* / Q000378:metabolism; D015497:HIV-1 / Q000737:chemistry*; D007128:Immunoglobulin Fragments / Q000737:chemistry / Q000378:metabolism; D007135:Immunoglobulin Variable Region / Q000737:chemistry / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009587:Nitrogen Isotopes; D010446:Peptide Fragments / Q000737:chemistry* / Q000276:immunology* / Q000378:metabolism; D011392:Proline / Q000737:chemistry; D011487:Protein Conformation; D012996:Solutions
D002247:Carbon Isotopes; D015483:HIV Antibodies; D015699:HIV Envelope Protein gp120; C059762:HIV envelope protein gp120 (305-321); D007128:Immunoglobulin Fragments; D007135:Immunoglobulin Variable Region; D009587:Nitrogen Isotopes; D010446:Peptide Fragments; D012996:Solutions; D011392:Proline