Ubiquitin-like proteins are conserved in eukaryotes and involved in numerous cellular processes. Ufm1 is proved to play important roles in endoplasmic reticulum homeostasis, vesicle transportation and embryonic development. Enzyme cascade of Ufm1 is similar to that of ubiquitin. Mature Ufm1 is activated and conjugated to substrates by assistance of Ufm1 activating enzyme Uba5 (E1), Ufm1 conjugating enzyme Ufc1 (E2), and Ufm1 ligating enzyme Ufl1 (E3). Here, we determined the solution structure of TbUfm1 from Trypanosoma brucei (T. brucei) by NMR spectroscopy and explored the interactions between TbUfm1 and TbUba5/TbUfc1/TbUfl1. TbUfm1 adopts a typical β-grasp fold, which partially wraps a central α-helix and the other two helixes. NMR chemical shift perturbation indicated that TbUfm1 interacts with TbUba5 via a hydrophobic pocket formed by α1α2β1β2. Although the structure and Uba5-interaction mode of TbUfm1 are conserved in Ufm1 proteins, there are also some differences, which might reflect the potential diversity of Ufm1 in evolution and biological functions.

泛素样蛋白在真核生物中是保守的，并参与许多细胞过程。Ufm1 被证明在内质网稳态、囊泡运输和胚胎发育中起重要作用。Ufm1 的酶级联反应类似于泛素的酶级联反应。在 Ufm1 激活酶 Uba5 (E1)、Ufm1 结合酶 Ufc1 (E2) 和 Ufm1 连接酶 Ufl1 (E3) 的帮助下，成熟的 Ufm1 被激活并结合到底物上。在这里，我们确定了来自布氏锥虫（T. brucei) 通过 NMR 光谱并探索了 TbUfm1 和 TbUba5/TbUfc1/TbUfl1 之间的相互作用。TbUfm1 采用典型的 β-抓握折叠，部分包裹一个中央 α-螺旋和其他两个螺旋。NMR 化学位移扰动表明 TbUfm1 通过由 α1α2β1β2 形成的疏水袋与 TbUba5 相互作用。尽管 TbUfm1 的结构和 Uba5 相互作用模式在 Ufm1 蛋白中是保守的，但也存在一些差异，这可能反映了 Ufm1 在进化和生物学功能方面的潜在多样性。