Logo of pnasPNASInfo for AuthorsSubscriptionsAboutThis Article
Proc Natl Acad Sci U S A. Oct 10, 1995; 92(21): 9843–9850.
PMCID: PMC40899

Structures of the apo- and the metal ion-activated forms of the diphtheria tox repressor from Corynebacterium diphtheriae.

Abstract

The diphtheria tox repressor (DtxR) of Corynebacterium diphtheriae plays a critical role in the regulation of diphtheria toxin expression and the control of other iron-sensitive genes. The crystal structures of apo-DtxR and of the metal ion-activated form of the repressor have been solved and used to identify motifs involved in DNA and metal ion binding. Residues involved in binding of the activated repressor to the diphtheria tox operator, glutamine 43, arginine 47, and arginine 50, were located and confirmed by site-directed mutagenesis. Previous biochemical and genetic data can be explained in terms of these structures. Conformational differences between apo- and Ni-DtxR are discussed with regard to the mechanism of action of this repressor.

Full text

Full text is available as a scanned copy of the original print version. Get a printable copy (PDF file) of the complete article (2.8M), or click on a page image below to browse page by page. Links to PubMed are also available for Selected References.

Images in this article

Click on the image to see a larger version.

Selected References

These references are in PubMed. This may not be the complete list of references from this article.
  • Litwin CM, Calderwood SB. Role of iron in regulation of virulence genes. Clin Microbiol Rev. 1993 Apr;6(2):137–149. [PMC free article] [PubMed]
  • Buck GA, Cross RE, Wong TP, Loera J, Groman N. DNA relationships among some tox-bearing corynebacteriophages. Infect Immun. 1985 Sep;49(3):679–684. [PMC free article] [PubMed]
  • Tao X, Boyd J, Murphy JR. Specific binding of the diphtheria tox regulatory element DtxR to the tox operator requires divalent heavy metal ions and a 9-base-pair interrupted palindromic sequence. Proc Natl Acad Sci U S A. 1992 Jul 1;89(13):5897–5901. [PMC free article] [PubMed]
  • Tao X, Murphy JR. Binding of the metalloregulatory protein DtxR to the diphtheria tox operator requires a divalent heavy metal ion and protects the palindromic sequence from DNase I digestion. J Biol Chem. 1992 Oct 25;267(30):21761–21764. [PubMed]
  • Tao X, Murphy JR. Determination of the minimal essential nucleotide sequence for diphtheria tox repressor binding by in vitro affinity selection. Proc Natl Acad Sci U S A. 1994 Sep 27;91(20):9646–9650. [PMC free article] [PubMed]
  • Schmitt MP, Holmes RK. Analysis of diphtheria toxin repressor-operator interactions and characterization of a mutant repressor with decreased binding activity for divalent metals. Mol Microbiol. 1993 Jul;9(1):173–181. [PubMed]
  • Wang Z, Schmitt MP, Holmes RK. Characterization of mutations that inactivate the diphtheria toxin repressor gene (dtxR). Infect Immun. 1994 May;62(5):1600–1608. [PMC free article] [PubMed]
  • Tao X, Schiering N, Zeng HY, Ringe D, Murphy JR. Iron, DtxR, and the regulation of diphtheria toxin expression. Mol Microbiol. 1994 Oct;14(2):191–197. [PubMed]
  • Schmitt MP, Holmes RK. Iron-dependent regulation of diphtheria toxin and siderophore expression by the cloned Corynebacterium diphtheriae repressor gene dtxR in C. diphtheriae C7 strains. Infect Immun. 1991 Jun;59(6):1899–1904. [PMC free article] [PubMed]
  • Qiu X, Verlinde CL, Zhang S, Schmitt MP, Holmes RK, Hol WG. Three-dimensional structure of the diphtheria toxin repressor in complex with divalent cation co-repressors. Structure. 1995 Jan 15;3(1):87–100. [PubMed]
  • Schiering N, Tao X, Murphy JR, Petsko GA, Ringe D. Crystallization and preliminary X-ray studies of the diphtheria Tox repressor from Corynebacterium diphtheriae. J Mol Biol. 1994 Dec 16;244(5):654–656. [PubMed]
  • Wang BC. Resolution of phase ambiguity in macromolecular crystallography. Methods Enzymol. 1985;115:90–112. [PubMed]
  • Zhang KY. SQUASH - combining constraints for macromolecular phase refinement and extension. Acta Crystallogr D Biol Crystallogr. 1993 Jan 1;49(Pt 1):213–222. [PubMed]
  • Jones TA, Zou JY, Cowan SW, Kjeldgaard M. Improved methods for building protein models in electron density maps and the location of errors in these models. Acta Crystallogr A. 1991 Mar 1;47(Pt 2):110–119. [PubMed]
  • Kabsch W, Mannherz HG, Suck D, Pai EF, Holmes KC. Atomic structure of the actin:DNase I complex. Nature. 1990 Sep 6;347(6288):37–44. [PubMed]
  • Ramachandran GN, Sasisekharan V. Conformation of polypeptides and proteins. Adv Protein Chem. 1968;23:283–438. [PubMed]
  • Bowie JU, Lüthy R, Eisenberg D. A method to identify protein sequences that fold into a known three-dimensional structure. Science. 1991 Jul 12;253(5016):164–170. [PubMed]
  • McKay DB, Steitz TA. Structure of catabolite gene activator protein at 2.9 A resolution suggests binding to left-handed B-DNA. Nature. 1981 Apr 30;290(5809):744–749. [PubMed]
  • Tao X, Murphy JR. Cysteine-102 is positioned in the metal binding activation site of the Corynebacterium diphtheriae regulatory element DtxR. Proc Natl Acad Sci U S A. 1993 Sep 15;90(18):8524–8528. [PMC free article] [PubMed]
  • Tao X, Zeng HY, Murphy JR. Transition metal ion activation of DNA binding by the diphtheria tox repressor requires the formation of stable homodimers. Proc Natl Acad Sci U S A. 1995 Jul 18;92(15):6803–6807. [PMC free article] [PubMed]
  • Pabo CO, Sauer RT. Protein-DNA recognition. Annu Rev Biochem. 1984;53:293–321. [PubMed]
  • Brennan RG, Matthews BW. The helix-turn-helix DNA binding motif. J Biol Chem. 1989 Feb 5;264(4):1903–1906. [PubMed]
  • Harrison SC. A structural taxonomy of DNA-binding domains. Nature. 1991 Oct 24;353(6346):715–719. [PubMed]
  • Wilson KP, Shewchuk LM, Brennan RG, Otsuka AJ, Matthews BW. Escherichia coli biotin holoenzyme synthetase/bio repressor crystal structure delineates the biotin- and DNA-binding domains. Proc Natl Acad Sci U S A. 1992 Oct 1;89(19):9257–9261. [PMC free article] [PubMed]
  • Schumacher MA, Choi KY, Zalkin H, Brennan RG. Crystal structure of LacI member, PurR, bound to DNA: minor groove binding by alpha helices. Science. 1994 Nov 4;266(5186):763–770. [PubMed]
  • Hochschild A, Irwin N, Ptashne M. Repressor structure and the mechanism of positive control. Cell. 1983 Feb;32(2):319–325. [PubMed]
  • Qian YQ, Billeter M, Otting G, Müller M, Gehring WJ, Wüthrich K. The structure of the Antennapedia homeodomain determined by NMR spectroscopy in solution: comparison with prokaryotic repressors. Cell. 1989 Nov 3;59(3):573–580. [PubMed]
  • Jordan SR, Pabo CO. Structure of the lambda complex at 2.5 A resolution: details of the repressor-operator interactions. Science. 1988 Nov 11;242(4880):893–899. [PubMed]
  • Aggarwal AK, Rodgers DW, Drottar M, Ptashne M, Harrison SC. Recognition of a DNA operator by the repressor of phage 434: a view at high resolution. Science. 1988 Nov 11;242(4880):899–907. [PubMed]
  • Otwinowski Z, Schevitz RW, Zhang RG, Lawson CL, Joachimiak A, Marmorstein RQ, Luisi BF, Sigler PB. Crystal structure of trp repressor/operator complex at atomic resolution. Nature. 1988 Sep 22;335(6188):321–329. [PubMed]
  • Schultz SC, Shields GC, Steitz TA. Crystal structure of a CAP-DNA complex: the DNA is bent by 90 degrees. Science. 1991 Aug 30;253(5023):1001–1007. [PubMed]
  • Arnold FH, Haymore BL. Engineered metal-binding proteins: purification to protein folding. Science. 1991 Jun 28;252(5014):1796–1797. [PubMed]
  • O'Halloran TV. Transition metals in control of gene expression. Science. 1993 Aug 6;261(5122):715–725. [PubMed]
  • Boyd JM, Hall KC, Murphy JR. DNA sequences and characterization of dtxR alleles from Corynebacterium diphtheriae PW8(-), 1030(-), and C7hm723(-). J Bacteriol. 1992 Feb;174(4):1268–1272. [PMC free article] [PubMed]

Articles from Proceedings of the National Academy of Sciences of the United States of America are provided here courtesy of National Academy of Sciences

Formats:

Related citations in PubMed

See reviews...See all...

Cited by other articles in PMC

See all...

Links

Recent Activity

Your browsing activity is empty.

Activity recording is turned off.

Turn recording back on

See more...