An XAS investigation of the nickel site structure in the transcriptional regulator InrS.

An XAS investigation of the nickel site structure in the transcriptional regulator InrS.
J Inorg Biochem. 2017 Aug 10;:
Authors: Carr CE, Foster AW, Maroney MJ
Abstract
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)2(Cys)2] 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).
PMID: 28844329 [PubMed - as supplied by publisher]

Source: Journal of Inorganic Biochemistry - August 10, 2017 Category: Biochemistry Authors: Carr CE, Foster AW, Maroney MJ Tags: J Inorg Biochem Source Type: research