Per-Arnt-Sim (PAS) domains occur in proteins from all kingdoms of life. In the bacterial kingdom, PAS domains are commonly positioned at the amino terminus of signaling proteins such as sensor histidine kinases, cyclic-di-GMP synthases/hydrolases, and methyl-accepting chemotaxis proteins. Although these domains are highly divergent at the primary sequence level, the structures of dozens of PAS domains across a broad section of sequence space have been solved, revealing a conserved three-dimensional architecture. An all-versus-all alignment of 63 PAS structures demonstrates that the PAS domain family forms structural clades on the basis of two principal variables: (a) topological location inside or outside the plasma membrane and (b) the class of small molecule that they bind. The binding of a chemically diverse range of small-molecule metabolites is a hallmark of the PAS domain family. PAS ligand binding either functions as a primary cue to initiate a cellular signaling response or provides the domain with the capacity to respond to secondary physical or chemical signals such as gas molecules, redox potential, or photons. This review synthesizes the current state of knowledge of the structural foundations and evolution of ligand recognition and binding by PAS domains.

中文翻译：

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基因组、细胞和结构背景中的配体结合 PAS 结构域。

Per-Arnt-Sim (PAS) 结构域存在于所有生命王国的蛋白质中。在细菌王国中，PAS 结构域通常位于信号蛋白的氨基末端，例如传感器组氨酸激酶、环二 GMP 合酶/水解酶和甲基接受趋化蛋白。尽管这些结构域在一级序列水平上存在很大差异，但跨广泛的序列空间部分的数十个 PAS 结构域的结构已经得到解决，揭示了保守的三维结构。63 个 PAS 结构的全部与全部比对表明，PAS 结构域家族根据两个主要变量形成结构分支：(a) 质膜内部或外部的拓扑位置，以及 (b) 它们所形成的小分子类别绑定。化学上多样化的小分子代谢物的结合是 PAS 结构域家族的标志。PAS 配体结合既可以作为启动细胞信号传导响应的主要线索，也可以为该结构域提供响应次级物理或化学信号（例如气体分子、氧化还原电位或光子）的能力。这篇综述综合了 PAS 结构域配体识别和结合的结构基础和进化的当前知识状态。