Abstract

The regulation of nucleotide-regulated inorganic pyrophosphatases at a molecular level has been extensively studied in order to establish the mechanism of signal transduction between the active and regulatory sites of these enzymes. However, this issue cannot be ultimately addressed because of the lack of reliable structural data on the full-length protein and its interactions with ligands. The low-resolution structure of nucleotide-regulated pyrophosphatase from Desulfitobacterium hafniense was determined for the first time by small-angle X-ray scattering. The structural changes in the full-length enzyme upon binding of adenosine monophosphate and diadenosine tetraphosphate were revealed. In dilute solutions the protein was found to exist as a stable homotetramer, the structure of which depends on the nature of the bound ligand. The structural data are important for an understanding of the molecular basis for regulation of this family of enzymes.

中文翻译：

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小角度X射线散射研究溶液中配体结合后来自哈弗脱硫杆菌的核苷酸调控焦磷酸酶季结构的变化

摘要

为了在这些酶的活性位点和调节位点之间建立信号转导机制，已经广泛研究了核苷酸调节的无机焦磷酸酶在分子水平上的调节。但是，由于缺乏有关全长蛋白及其与配体相互作用的可靠结构数据，因此无法最终解决此问题。哈夫脱硫杆菌的核苷酸调控焦磷酸酶的低分辨率结构是通过小角度X射线散射首次确定的。揭示了在单磷酸腺苷和四磷酸二腺苷结合后全长酶的结构变化。在稀溶液中，发现蛋白质以稳定的均四聚体形式存在，其结构取决于结合的配体的性质。结构数据对于理解调节该酶家族的分子基础很重要。