Diphtheria toxin repressor (DtxR) is a transition metal ion-activated repressor in Corynebacterium diphtheriae. DtxR is an iron sensor; metal-bound DtxR represses transcription of genes downstream of the tox operator. Wild-type DtxR [DtxR(wt)] and several mutant forms were overexpressed and purified from Escherichia coli. DtxR was isolated without bound metal. Metal reconstitution gave a binding stoichiometry of 2 per monomer for DtxR(wt) and 1 per monomer for DtxR(H79A) and DtxR(M10A). DNA binding of DtxR(H79A) and DtxR(M10A) indicates that metal site 2 is essential for activity. Metal binding lowers the dimerization K(d) of DtxR from low micromolar to 33 nM. Gel electrophoretic mobility-shift assays show that Fe(2+) and not Fe(3+) activates DtxR for DNA binding. This finding suggests that gene regulation by DtxR may be sensitive not only to iron levels but also to redox state of the iron. Mutations in the tox operator sequence indicate that DtxR dimers binding to DNA may be highly cooperative.
This research output has an Altmetric Attention Score of 4. This is our high-level measure of the quality and quantity of online attention that it has received. This Attention Score, as well as the ranking and number of research outputs shown below, was calculated when the research output was last mentioned on 11 January 2016.
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Outputs from Proceedings of the National Academy of Sciences of the United States of America
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Outputs of similar age from Proceedings of the National Academy of Sciences of the United States of America
#417
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Altmetric has tracked 34,363,559 research outputs across all sources so far. This one has received more attention than most of these and is in the 64th percentile.
So far Altmetric has tracked 118,931 research outputs from this source. They typically receive a lot more attention than average, with a mean Attention Score of 40.1. This one is in the 29th percentile – i.e., 29% of its peers scored the same or lower than it.
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We're also able to compare this research output to 592 others from the same source and published within six weeks on either side of this one. This one is in the 28th percentile – i.e., 28% of its contemporaries scored the same or lower than it.
