1xcv

From Proteopedia

Crystal Structure Of (H79AC102D)Dtxr complexed with Nickel(II)

Structural highlights

1xcv is a 1 chain structure with sequence from Corynebacterium diphtheriae. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:	X-ray diffraction, Resolution 2.1Å
Ligands:
Resources:	FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

DTXR_CORDI Iron-binding repressor of the dipheteria toxin gene expression. May serve as a global regulator of gene expression. Represses ripA under iron excess.

Evolutionary Conservation

Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.

Publication Abstract from PubMed

The diphtheria toxin repressor (DtxR) is a metal ion-activated transcriptional regulator that has been linked to the virulence of Corynebacterium diphtheriae. Structure determination has shown that there are two metal ion binding sites per repressor monomer, and site-directed mutagenesis has demonstrated that binding site 2 (primary) is essential for recognition of the target DNA repressor, leaving the role of binding site 1 (ancillary) unclear. Calorimetric techniques have demonstrated that although binding site 1 (ancillary) has high affinity for metal ion with a binding constant of 2 x 10(-7), binding site 2 (primary) is a low-affinity binding site with a binding constant of 6.3 x 10(-4). These two binding sites act in an independent fashion, and their contribution can be easily dissected by traditional mutational analysis. Our results clearly demonstrate that binding site 1 (ancillary) is the first one to be occupied during metal ion activation, playing a critical role in stabilization of the repressor. In addition, structural data obtained for the mutants Ni-DtxR(H79A,C102D), reported here, and the previously reported DtxR(H79A) have allowed us to propose a mechanism of metal activation for DtxR.

Mechanism of metal ion activation of the diphtheria toxin repressor DtxR.,D'Aquino JA, Tetenbaum-Novatt J, White A, Berkovitch F, Ringe D Proc Natl Acad Sci U S A. 2005 Dec 20;102(51):18408-13. Epub 2005 Dec 13. PMID:16352732^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

References

↑ D'Aquino JA, Tetenbaum-Novatt J, White A, Berkovitch F, Ringe D. Mechanism of metal ion activation of the diphtheria toxin repressor DtxR. Proc Natl Acad Sci U S A. 2005 Dec 20;102(51):18408-13. Epub 2005 Dec 13. PMID:16352732