Tugarinov V, Anglister J
a Department of Structural Biology , The Weizmann Institute of Science , Rehovot , 76100 , Israel.
J Biomol Struct Dyn. 2000;17 Suppl 1:57-63. doi: 10.1080/07391102.2000.10506604.
Abstract The refined solution structure of a peptide representing the full epitope of the HIV-1(IIIB) V3 loop in complex with the anti-gp120 antibody Fv fragment was determined using isotope-filtered and isotope-edited NMR. Both the (15)N-labeled peptide in complex with the unlabeled Fv and the unlabeled peptide complexed with the uniformly (15)N,(13)C-labeled Fv were investigated. The backbone of the bound peptide adopts a well defined β-hairpin conformation with two twisted anti-parallel β-strands linked by a type VI tight turn comprising residues RGPG. The central glycine and proline residues of the turn are linked by a cis peptide bond. (15)N{(1)H} NOE measurements demonstrated that the backbone of the bound peptide including the central QRGPGR loop is well ordered in the bound state. The V3 loop peptide solution structure is significantly different from the peptide conformation in the X-ray structures of three anti-peptide antibody/V3(MN) peptide complexes. These differences seem to be dictated by the antibody dependence and HIV strain-specificity of the V3 peptide fold.
摘要 采用同位素过滤和同位素编辑核磁共振技术，测定了与抗gp120抗体Fv片段复合的、代表HIV-1（IIIB）V3环完整表位的肽段的精细溶液结构。研究了与未标记Fv复合的（15）N标记肽段以及与均匀（15）N、（13）C标记Fv复合的未标记肽段。结合肽段的主链呈现出明确的β-发夹构象，由两个扭曲的反平行β-链通过包含RGPG残基的VI型紧密转角相连。转角处的中心甘氨酸和脯氨酸残基通过顺式肽键相连。（15）N{（1）H} NOE测量表明，结合肽段的主链包括中心QRGPGR环在结合状态下排列有序。V3环肽段的溶液结构与三种抗肽抗体/V3（MN）肽段复合物的X射线结构中的肽段构象显著不同。这些差异似乎由V3肽段折叠的抗体依赖性和HIV毒株特异性所决定。
