Structural basis of enhanced binding of extended and helically constrained peptide epitopes of the broadly neutralizing HIV-1 antibody 4E10
Structural basis of enhanced binding of extended and helically constrained peptide epitopes of the broadly neutralizing HIV-1 antibody 4E10
复制标题
DOI：
10.1016/j.jmb.2006.10.088
复制
发表时间：
2007-02-02
影响因子：
5.6
通讯作者：
Wilson, Ian A.
中科院分区：
文献类型：
--
作者：
Cardoso, Rosa M. F.;Brunel, Florence M.;Wilson, Ian A.
有效的、广泛的HIV-1中和抗体（nAb）对于艾滋病疫苗的设计可能是非常宝贵的。4 E10是迄今为止已知的最广泛的HIV-1 nAb，识别gp 41近膜区中的连续且高度保守的螺旋表位。因此，4 E10表位是疫苗设计的极好靶标，因为它也非常适合肽工程以增强其螺旋特性。为了研究增加肽长度和在4 E10表位中引入螺旋促进限制的结构效应，我们已经确定了与优化的肽表位结合的Fab 4 E10的晶体结构（NWFDITNWLWYIKKKK-NH 2），Aib限制性肽表位（NWFDITNAibLWRR-NH 2）和硫醚连接肽（NWFCITOWLWKKK-NH 2）分别达到1.7埃、2.1埃和2.2埃的分辨率。硫醚连接肽是首次报道的与抗体结合的环状拴系螺旋肽结构。引入的螺旋约束限制了肽的构象灵活性，而不影响与4 E10的相互作用。亲和力的显著增加（10 nM与原始KGND肽模板的IC 50的10（4）nM）主要是通过4 E10与肽C末端额外螺旋转角（包括Leu 679和Trp 680）的相互作用实现的。因此，核心4 E10表位被延伸并修饰为WFX（I/L）（T/S）XX（L/I）W基序，其中X在4 E10结合中不起主要作用，并且可用于在肽表位中引入螺旋促进约束。(c)2006爱思唯尔有限公司保留所有权利。
Potent, broadly HIV-1 neutralizing antibodies (nAbs) may be invaluable for the design of an AIDS vaccine. 4E10 is the broadest HIV-1 nAb known to date and recognizes a contiguous and highly conserved helical epitope in the membrane-proximal region of gp41. The 4E10 epitope is thus an excellent target for vaccine design as it is also highly amenable to peptide engineering to enhance its helical character. To investigate the structural effect of both increasing the peptide length and of introducing helixpromoting constraints in the 4E10 epitope, we have determined crystal structures of Fab 4E10 bound to an optimized peptide epitope (NWFDITNWLWYIKKKK-NH2), an Aib-constrained peptide epitope (NWFDITNAibLWRR-NH2), and a thioether-linked peptide (NWFCITOWLWKKKK-NH2) to resolutions of 1.7 angstrom, 2.1 angstrom, and 2.2 angstrom, respectively. We thioether-linked peptide is the first reported structure of a cyclic tethered helical peptide bound to an antibody. The introduced helix constraints limit the conformational flexibility of the peptides without affecting interactions with 4E10. The substantial increase in affinity (10 nM versus 10(4) nM of the IC50 of the original KGND pepticle template) is largely realized by 4E10 interaction with an additional helical turn at the peptide C terminus that includes Leu679 and Trp680. Thus, the core 4E10 epitope was extended and modified to a WFX(I/L)(T/S)XX(L/I)W motif, where X does not play a major role in 4E10 binding and can be used to introduce helicalpromoting constraints in the peptide epitope. (c) 2006 Elsevier Ltd. All rights reserved.