Tugarinov V, Zvi A, Levy R, Anglister J
Department of Structural Biology, The Weizmann Institute of Science, Rehovot, Israel.
Nat Struct Biol. 1999 Apr;6(4):331-5. doi: 10.1038/7567.
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.
一种18个残基的HIV-1IIIB V3肽与抗gp120抗体的Fv片段形成复合物的精细溶液结构揭示了一种意想不到的VI型β-转角，其位于β-发夹结构的中心，由RGPG残基组成。该转角的中心甘氨酸和脯氨酸通过顺式肽键相连。该转角的残基与抗体Fv广泛相互作用。15N[1H] NOE测量表明，该肽的主链，包括中心的QRGPGR环，在复合物中排列有序。该溶液结构与HIV-1MN V3肽与抗肽抗体结合的X射线结构有显著差异。这些差异可能是由于HIV-1IIIB毒株的GPGR序列之前有两个残基（QR）插入，以及抗gp120抗体固定的肽表位长得多所致。
