The recently discovered Rrf2 family transcriptional regulator RsrR coordinates a [2Fe-2S] cluster. Remarkably, binding of the protein to RsrR-regulated promoter DNA sequences is switched on and off through the facile cycling of the {2Fe-2S] cluster between +2 and +1 states. Here, we report high resolution crystal structures of the RsrR dimer, revealing that the [2Fe-2S] cluster is asymmetrically coordinated across the RsrR monomer-monomer interface by two Cys residues from one subunit and His and Glu residues from the other. To our knowledge, this is the first example of a protein bound [Fe-S] cluster with three different amino acid side chains as ligands, and of Glu acting as ligand to a [2Fe-2S] cluster. Analyses of RsrR structures revealed a conformational change, centered on Trp9, which results in a significant shift in the DNA-binding helix-turn-helix region.
CITATION STYLE
Volbeda, A., Martinez, M. T. P., Crack, J. C., Amara, P., Gigarel, O., Munnoch, J. T., … Fontecilla-Camps, J. C. (2019). Crystal Structure of the Transcription Regulator RsrR Reveals a {2Fe-2S] Cluster Coordinated by Cys, Glu, and His Residues. Journal of the American Chemical Society, 141(6), 2367–2375. https://doi.org/10.1021/jacs.8b10823
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