Transmembrane (TM) domains as simple as a single span can perform complex biological functions using entirely lipid-embedded chemical features. Computational design has the potential to generate custom tool molecules directly targeting membrane proteins at their functional TM regions. Thus far, designed TM domain-targeting agents have been limited to mimicking the binding modes and motifs of natural TM interaction partners. Here, we demonstrate the design of de novo TM proteins targeting the erythropoietin receptor (EpoR) TM domain in a custom binding topology competitive with receptor homodimerization. The TM proteins expressed in mammalian cells complex with EpoR and inhibit erythropoietin-induced cell proliferation. In vitro, the synthetic TM domain complex outcompetes EpoR homodimerization. Structural characterization reveals that the complex involves the intended amino acids and agrees with our designed molecular model of antiparallel TM helices at 1:1 stoichiometry. Thus, membrane protein TM regions can now be targeted in custom-designed topologies.

像单个跨度一样简单的跨膜（TM）结构域可以利用完全脂质嵌入的化学特征来执行复杂的生物功能。计算设计有可能生成直接靶向膜蛋白功能 TM 区域的定制工具分子。迄今为止，设计的TM结构域靶向剂仅限于模仿天然TM相互作用伙伴的结合模式和基序。在这里，我们展示了以与受体同二聚化竞争的定制结合拓扑结构靶向促红细胞生成素受体（EpoR）TM结构域的从头TM蛋白的设计。哺乳动物细胞中表达的TM蛋白与EpoR复合并抑制促红细胞生成素诱导的细胞增殖。在体外，合成的 TM 结构域复合物胜过 EpoR 同二聚化。结构表征表明，该复合物涉及预期的氨基酸，并且与我们设计的 1:1 化学计量的反平行 TM 螺旋分子模型一致。因此，现在可以在定制设计的拓扑中靶向膜蛋白 TM 区域。