XAS 研究转录调控因子 InrS 中镍位点结构
An XAS investigation of the nickel site structure in the transcriptional regulator InrS.
机构信息
Chemistry Department, University of Massachusetts Amherst, MA 01003, USA.
Department of Biosciences, Durham University, Durham, UK; Department of Chemistry, Durham University, Durham, UK.
出版信息
J Inorg Biochem. 2017 Dec;177:352-358. doi: 10.1016/j.jinorgbio.2017.08.003. Epub 2017 Aug 10.
InrS (Internal nickel-responsive Sensor) is a transcriptional repressor of the nickel exporter NrsD and de-represses expression of the exporter upon binding Ni(II) ions. Although a crystal structure of apo-InrS has been reported, no structure of the protein with metal ions bound is available. Herein we report the results of metal site structural investigations of Ni(II) and Cu(II) complexes of InrS using X-ray absorption spectroscopy (XAS) that are complementary to data available from the apo-InrS crystal structure, and are consistent with a planar four-coordinate [Ni(His)(Cys)] structure, where the ligands are derived from the side chains of His21, Cys53, His78, and Cys82. Coordination of Cu(II) to InrS forms a nearly identical planar four-coordinate complex that is consistent with a simple replacement of the Ni(II) center by Cu(II).
InrS（内部镍响应传感器）是镍外排蛋白 NrsD 的转录抑制剂，在结合 Ni(II) 离子后解除对该外排蛋白的抑制。虽然已报道了 apo-InrS 的晶体结构，但没有结合金属离子的蛋白质结构的可用数据。本文报道了使用 X 射线吸收光谱法（XAS）对 Ni(II) 和 Cu(II) 配合物的金属位点结构进行研究的结果，这些结果与 apo-InrS 晶体结构的数据互补，并且与平面四配位 [Ni(His)(Cys)] 结构一致，其中配体来自 His21、Cys53、His78 和 Cys82 的侧链。Cu(II)与 InrS 的配位形成几乎相同的平面四配位络合物，这与 Ni(II)中心被 Cu(II)简单取代一致。
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