Department of Chemistry, University of Konstanz, Constance, Germany.
Konstanz Research School Chemical Biology KoRS-CB, University of Konstanz, Constance, Germany.
Protein Sci. 2022 Apr;31(4):811-821. doi: 10.1002/pro.4269. Epub 2022 Jan 12.
Eps15 homology (EH) domains are universal interaction domains to establish networks of protein-protein interactions in the cell. These networks mainly coordinate cellular functions including endocytosis, actin remodeling, and other intracellular signaling pathways. They are well characterized in structural terms, except for the internal EH domain from human γ-synergin (EHγ). Here, we complete the family of EH domain structures by determining the solution structure of the EHγ domain. The structural ensemble follows the canonical EH domain fold and the identified binding site is similar to other known EH domains. But EHγ differs significantly in the N- and C-terminal regions. The N-terminal α-helix is shortened compared to known homologues, while the C-terminal one is fully formed. A significant proportion of the remaining N- and C-terminal regions are well structured, a feature not seen in other EH domains. Single mutations in both the N-terminal and the C-terminal structured extensions lead to the loss of the distinct three-dimensional fold and turn EHγ into a molten globule like state. Therefore, we propose that the structural extensions in EHγ function as a clamp and are undoubtedly required to maintain its tertiary fold.
EH 结构域是普遍存在的蛋白质相互作用域，可在细胞内建立蛋白质-蛋白质相互作用网络。这些网络主要协调细胞功能，包括内吞作用、肌动蛋白重塑和其他细胞内信号通路。EH 结构域在结构上已经得到了很好的描述，除了人类 γ-突触融合蛋白（γ-synergin）的内部 EH 结构域（EHγ）。在这里，我们通过确定 EHγ 结构域的溶液结构来完成 EH 结构域家族的结构特征。结构整体遵循典型的 EH 结构域折叠，并且鉴定的结合位点与其他已知的 EH 结构域相似。但是，EHγ 在 N 端和 C 端区域有很大的不同。与已知同源物相比，N 端的α-螺旋缩短，而 C 端的α-螺旋完全形成。剩余 N 端和 C 端区域的很大一部分具有很好的结构，这在其他 EH 结构域中没有出现。N 端和 C 端结构延伸中的单个突变会导致独特的三维折叠丢失，并使 EHγ 变成类似无规卷曲的状态。因此，我们提出 EHγ 中的结构延伸作为一个夹子，无疑需要维持其三级结构。
