Trichobakin (TBK) is a type-I ribosome-inactivating protein (RIP-I), acting as an extremely potent inhibitor of protein synthesis in the cell-free translation system of rabbit reticulocyte lysate (IC₅₀: 3.5 pM). In this respect, TBK surpasses the well-studied highly homologous RIP-I trichosanthin (IC₅₀: 20–27 pM), therefore creation of recombinant toxins based on it is of great interest. TBK needs to penetrate into cytosol through the cell membrane and specifically bind to α-sarcin/ricin loop of 28S ribosome RNA to perform the function of specific RNA depurination. At the moment, there is no detailed structural-dynamic information in solution about diverse states RIP-I can adopt at different stages on the way to protein synthesis inhibition. In this work, we report a near-complete assignment of ¹H, ¹³C, and ¹⁵N TBK (27.3 kDa) resonances and analysis of the secondary structure based on the experimental chemical shifts data. This work will serve as a basis for further investigations of the structure, dynamics and interactions of the TBK with its molecular partners using NMR techniques.

中文翻译：

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核糖体失活蛋白滴虫蛋白（TBK）的骨架和侧链化学位移分配。

Trichobakin（TBK）是一种I型核糖体失活蛋白（RIP-1），在兔网织红细胞裂解物的无细胞翻译系统中起非常有效的蛋白质合成抑制剂作用（IC ₅₀：3.5 pM）。在这方面，TBK超过了经过充分研究的高度同源的RIP-1天花粉蛋白（IC ₅₀：20–27 pM），因此，基于它的重组毒素的产生引起了极大的兴趣。TBK需要通过细胞膜渗透到细胞质中，并特异性结合28S核糖体RNA的α-sarcin/ ricin环，以执行特定RNA纯化的功能。目前，在解决方案中没有关于RIP-1在蛋白质合成抑制途径的不同阶段可以采用的不同状态的详细结构动力学信息。在这项工作中，我们报告了¹ H，¹³ C和¹⁵的接近完成的分配N TBK（27.3 kDa）共振和基于实验化学位移数据的二级结构分析。这项工作将作为进一步研究TBK及其分子伴侣的结构，动力学和相互作用的基础。