MOE Key Laboratory for Non-equilibrium Synthesis and Modulation of Condensed Matter, School of Science, Xi'an Jiaotong University, Xi'an 710049, China.
Sci Rep. 2013;3:1089. doi: 10.1038/srep01089. Epub 2013 Jan 21.
Peptides show much promise as potent and selective drug candidates. Fusing peptides to a scaffold monoclonal antibody produces a conjugated antibody which has the advantages of peptide activity yet also has the pharmacokinetics determined by the scaffold antibody. However, the conjugated antibody often has poor binding affinity to antigens that may be related to unknown structural changes. The study of the conformational change is difficult by conventional techniques because structural fluctuation under equilibrium results in multiple structures co-existing. Here, we employed our two recently developed electron microscopy (EM) techniques: optimized negative-staining (OpNS) EM and individual-particle electron tomography (IPET). Two-dimensional (2D) image analyses and three-dimensional (3D) maps have shown that the domains of antibodies present an elongated peptide-conjugated conformational change, suggesting that our EM techniques may be novel tools to monitor the structural conformation changes in heterogeneous and dynamic macromolecules, such as drug delivery vehicles after pharmacological synthesis and development.
肽作为有效且具有选择性的候选药物具有很大的潜力。将肽融合到支架单克隆抗体上会产生缀合抗体，该抗体具有肽的活性，同时还具有支架抗体决定的药代动力学特性。然而，缀合抗体通常对可能与未知结构变化有关的抗原的结合亲和力较差。由于平衡下的结构波动会导致多种结构共存，因此传统技术难以研究构象变化。在这里，我们采用了我们最近开发的两种电子显微镜 (EM) 技术：优化的负染色 (OpNS) EM 和单颗粒电子断层扫描 (IPET)。二维 (2D) 图像分析和三维 (3D) 图谱表明，抗体的结构域呈现出伸长的肽缀合构象变化，这表明我们的 EM 技术可能是监测药物输送载体等异质和动态大分子的结构构象变化的新工具，如在药理学合成和开发后。
