English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

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.

Metal stoichiometry and functional studies of the diphtheria toxin repressor