Prevalence of one or more partially folded intermediates during protein unfolding with different secondary and ternary conformations has been identified as an integral character of protein unfolding. These transition-state species need to be characterized structurally for elucidation of their folding pathways. We have determined the three-dimensional structure of an intermediate state with increased conformational space sampling under urea-denaturing condition. The protein unfolds completely at 10 M urea but retains residual secondary structural propensities with restricted motion. Here, we describe the native state, observable intermediate state, and unfolded state for ETR-3 RRM-3, which has canonical RRM fold. These observations can shed more light on unfolding events for RRM-containing proteins.

中文翻译：

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ETR-3 蛋白 RRM 结构域的未折叠中间体的结构揭示了其天然样折叠

在具有不同二级和三元构象的蛋白质解折叠过程中，一种或多种部分折叠中间体的普遍存在已被确定为蛋白质解折叠的一个整体特征。这些过渡态物种需要在结构上进行表征以阐明它们的折叠途径。我们已经确定了在尿素变性条件下增加构象空间采样的中间状态的三维结构。该蛋白质在 10 M 尿素中完全展开，但保留了运动受限的残留二级结构倾向。在这里，我们描述了具有规范 RRM 折叠的 ETR-3 RRM-3 的原生状态、可观察的中间状态和未折叠状态。这些观察结果可以为含 RRM 的蛋白质的展开事件提供更多信息。