Stable Docking of Neutralizing Human Immunodeficiency Virus Type 1 gp41 Membrane-Proximal External Region Monoclonal Antibodies 2F5 and 4E10 Is Dependent on the Membrane Immersion Depth of Their Epitope Regions
Stable Docking of Neutralizing Human Immunodeficiency Virus Type 1 gp41 Membrane-Proximal External Region Monoclonal Antibodies 2F5 and 4E10 Is Dependent on the Membrane Immersion Depth of Their Epitope Regions
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DOI：
10.1128/jvi.00571-09
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发表时间：
2009-10-01
影响因子：
5.4
通讯作者：
Alam, S. Munir
中科院分区：
文献类型：
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作者：
Dennison, S. Moses;Stewart, Shelley M.;Alam, S. Munir
中和抗体2F5和4E10与人类免疫缺陷病毒1型（HIV-1） gp41的结合涉及病毒膜和gp41膜近端外区（MPER）表位。在这项研究中，我们使用了几种生物物理工具来检查gp41 MPER肽在脂质体中的二级结构、取向和浸泡深度，并确定MPER与脂质的取向如何影响单克隆抗体（MAbs） 2F5和4E10的结合动力学。2F5和4E10结合到各自的名义表位和双表位（包括2F5和4E10表位）的MPER肽-脂质体缀合物最好的描述是两步接触对接模型。结合动力学分析和温度对2F5和4E10与MPER肽-脂质体偶联物结合稳定性的影响表明，4E10的对接速度相对较慢，热力学上不太有利。荧光猝灭和荧光共振能量转移实验结果表明，2F5表位更多地暴露在溶剂中，而4E10表位则浸泡在脂质双分子层的极性界面区。圆二色光谱研究表明，名义表位和双表位MPER肽锚定在脂质体上时采用具有不同螺旋内容的有序结构。此外，通过疏水锚定序列将MPER肽锚定到膜上是有效的单抗对接所必需的。这些结果支持了2F5和4E10与膜脂结合的能力是与膜嵌入的MPER残基稳定对接所必需的模型。这些数据对设计和使用肽脂质体偶联物作为诱导mper中和抗体的免疫原具有重要意义。
The binding of neutralizing antibodies 2F5 and 4E10 to human immunodeficiency virus type 1 (HIV-1) gp41 involves both the viral membrane and gp41 membrane proximal external region (MPER) epitopes. In this study, we have used several biophysical tools to examine the secondary structure, orientation, and depth of immersion of gp41 MPER peptides in liposomes and to determine how the orientation of the MPER with lipids affects the binding kinetics of monoclonal antibodies (MAbs) 2F5 and 4E10. The binding of 2F5 and 4E10 both to their respective nominal epitopes and to a biepitope ( includes 2F5 and 4E10 epitopes) MPER peptide-liposome conjugate was best described by a two-step encounter-docking model. Analysis of the binding kinetics and the effect of temperature on the binding stability of 2F5 and 4E10 to MPER peptide-liposome conjugates revealed that the docking of 4E10 was relatively slower and thermodynamically less favorable. The results of fluorescence-quenching and fluorescence resonance energy transfer experiments showed that the 2F5 epitope was more solvent exposed, whereas the 4E10 epitope was immersed in the polar-apolar interfacial region of the lipid bilayer. A circular dichroism spectroscopic study demonstrated that the nominal epitope and biepitope MPER peptides adopted ordered structures with differing helical contents when anchored to liposomes. Furthermore, anchoring of MPER peptides to the membrane via a hydrophobic anchor sequence was required for efficient MAb docking. These results support the model that the ability of 2F5 and 4E10 to bind to membrane lipid is required for stable docking to membrane-embedded MPER residues. These data have important implications for the design and use of peptide-liposome conjugates as immunogens for the induction of MPER-neutralizing antibodies.