Structure analysis of high-molecular weight intrinsically disordered proteins using 13C detection NMR approach

我们用~(13)C和~1H检测核磁共振方法对酵母细胞中常见的转录因子Tfa2进行了分析。在这项工作中，我们特别关注Tfa2中的内在无序部分，它与中介复合体中的Gal11亚基结合。利用13C和15N进化轴解决了ID段典型的严重信号重叠，其化学位移比蛋白质中的其他核自旋具有显著的分散性。我们发现Tfa2的介体结合域Tfa2-Mbd瞬时形成三螺旋结构。瞬时结构的形成是由其同源二聚体的形成所介导的。我们还发现瞬时折叠结构具有与Gal11结合的能力，缺乏瞬时折叠能力的突变体不与Gal11结合。总体而言，本研究证明了与Tfa2中ID部分相关的独特结构和功能特性。

We analyzed one of the general transcription factors in yeast cell, Tfa2, with the 13C and 1H detection NMR methods. In this work, we particularly focused on the intrinsically disordered part in Tfa2, which binds to Gal11 subunit in the Mediator complex. The severe signal overlaps typically found for the ID segment were solved using the 13C and 15N evolution axes, whose chemical shifts have significant dispersions over the other nuclear spins in protein.We found the Mediator binding domain of Tfa2, Tfa2-mbd, transiently forms three-helix structure. The transient structure formation was mediated by its homo-dimer formation. We also found that the transiently folded structure has binding ability to Gal11; the mutant that lacks the transient folding ability does not bind to Gal11. Over all, the present research has demonstrated the unique structural and functional properties associated with the ID part in Tfa2.