Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan.
Laboratory of Medicinal Chemistry, Kyoto Pharmaceutical University, Yamashina-ku, Kyoto 607-8412, Japan.
Bioconjug Chem. 2024 Aug 21;35(8):1190-1199. doi: 10.1021/acs.bioconjchem.4c00204. Epub 2024 Jul 23.
Interleukin-6 (IL-6), a multifunctional cytokine, is an attractive therapeutic target for immunological and inflammatory diseases. We investigated the chemical synthesis of IL-6 and its enantiomer (d-IL-6) using a sequential N-to-C native chemical ligation strategy from six peptide segments. Solubilizing Trt-K tags improved the intermediate solubility and served as protecting groups during the metal-free desulfurization to facilitate the synthesis of full-length IL-6 protein. Synthetic l-IL-6 and recombinant IL-6 exhibited nearly identical structural and binding properties. The symmetrical binding property of d-IL-6 was also demonstrated by functional analysis using IL-6-binding peptides. The resulting functional d-IL-6 was employed to screen a phage-displayed antibody fragment library, leading to the identification of several d-IL-6-binding single-domain antibodies. This work will contribute to the development of novel, potent IL-6 inhibitors without the adverse effects of undesired immune activation.
白细胞介素 6（IL-6）是一种多功能细胞因子，是免疫和炎症性疾病有吸引力的治疗靶点。我们使用从六个肽段的顺序 N 到 C 天然化学连接策略研究了 IL-6 及其对映异构体（d-IL-6）的化学合成。使用 Trt-K 标签溶解提高了中间体的溶解度，并在无金属脱硫过程中作为保护基团，以促进全长 IL-6 蛋白的合成。合成的 l-IL-6 和重组 IL-6 表现出几乎相同的结构和结合特性。通过使用 IL-6 结合肽的功能分析也证明了 d-IL-6 的对称结合特性。所得功能 d-IL-6 用于筛选噬菌体展示抗体片段文库，导致鉴定出几种 d-IL-6 结合单域抗体。这项工作将有助于开发新型、有效的 IL-6 抑制剂，而不会产生不必要的免疫激活的不良反应。
