Laboratory of Physical Chemistry of Biomolecules, UCPTS, University of Namur, Rue de Bruxelles 61, B-5000 Namur, Belgium; Namur Research Institute for Life Sciences (NARILIS), University of Namur, Namur, Belgium; Namur Institute of Structured Matter (NISM), University of Namur, Namur, Belgium; GIGA-Molecular Biology of Diseases, Molecular Analysis of Gene Expression (MAGE) Laboratory, University of Liege, B34, Avenue de l'Hôpital, B-4000 Liège, Belgium.
Laboratory of Physical Chemistry of Biomolecules, UCPTS, University of Namur, Rue de Bruxelles 61, B-5000 Namur, Belgium; Namur Research Institute for Life Sciences (NARILIS), University of Namur, Namur, Belgium; Namur Institute of Structured Matter (NISM), University of Namur, Namur, Belgium.
Int J Biol Macromol. 2024 Oct;277(Pt 3):134291. doi: 10.1016/j.ijbiomac.2024.134291. Epub 2024 Jul 30.
Tuftelin Interacting Protein 11 (TFIP11) was identified as a critical human spliceosome assembly regulator, interacting with multiple proteins and localising in membrane-less organelles. However, a lack of structural information on TFIP11 limits the rationalisation of its biological role. TFIP11 is predicted as an intrinsically disordered protein (IDP), and more specifically concerning its N-terminal (N-TER) region. IDPs lack a defined tertiary structure, existing as a dynamic conformational ensemble, favouring protein-protein and protein-RNA interactions. IDPs are involved in liquid-liquid phase separation (LLPS), driving the formation of subnuclear compartments. Combining disorder prediction, molecular dynamics, and spectroscopy methods, this contribution shows the first evidence TFIP11 N-TER is a polyampholytic IDP, exhibiting a structural duality with the coexistence of ordered and disordered assemblies, depending on the ionic strength. Increasing the salt concentration enhances the protein conformational flexibility, presenting a more globule-like shape, and a fuzzier unstructured arrangement that could favour LLPS and protein-RNA interaction. The most charged and hydrophilic regions are the most impacted, including the G-Patch domain essential to TFIP11 function. This study gives a better understanding of the salt-dependent conformational behaviour of the N-TER TFIP11, supporting the hypothesis of the formation of different types of protein assembly, in line with its multiple biological roles.
Tuftelin 相互作用蛋白 11（TFIP11）被鉴定为关键的人类剪接体组装调节剂，与多种蛋白质相互作用，并定位于无膜细胞器中。然而，由于缺乏关于 TFIP11 的结构信息，限制了对其生物学作用的合理化解释。TFIP11 被预测为一种固有无序蛋白（IDP），更具体地说是其 N 端（N-TER）区域。IDP 缺乏明确的三级结构，存在于动态构象集合中，有利于蛋白质-蛋白质和蛋白质-RNA 相互作用。IDP 参与液-液相分离（LLPS），驱动亚核隔室的形成。本研究结合无序预测、分子动力学和光谱学方法，首次证明 TFIP11 N-TER 是一种多两性 IDP，表现出结构双重性，有序和无序组装共存，取决于离子强度。增加盐浓度会增强蛋白质构象的灵活性，呈现出更类似球蛋白的形状和更模糊的无规构象排列，这可能有利于 LLPS 和蛋白质-RNA 相互作用。受影响最大的是最带电荷和最亲水的区域，包括对 TFIP11 功能至关重要的 G 斑结构域。这项研究更好地理解了 N-TER TFIP11 的盐依赖性构象行为，支持了形成不同类型蛋白质组装的假说，与它的多种生物学作用一致。
