2tdx
From Proteopedia
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==Overview== | ==Overview== | ||
| - | The virulent phenotype of the pathogenic bacterium Corynebacterium | + | The virulent phenotype of the pathogenic bacterium Corynebacterium diphtheriae is conferred by diphtheria toxin, whose expression is an adaptive response to low concentrations of iron. The expression of the toxin gene (tox) is regulated by the repressor DtxR, which is activated by transition metal ions. X-ray crystal structures of DtxR with and without (apo-form) its coordinated transition metal ion have established the general architecture of the repressor, identified the location of the metal-binding sites, and revealed a metal-ion-triggered subunit-subunit 'caliper-like' conformational change. Here we report the three-dimensional crystal structure of the complex between a biologically active Ni(II)-bound DtxR(C102D) mutant, in which a cysteine is replaced by an aspartate at residue 102, and a 33-base-pair DNA segment containing the toxin operator toxO. This structure shows that DNA interacts with two dimeric repressor proteins bound to opposite sides of the tox operator. We propose that a metal-ion-induced helix-to-coil structural transition in the amino-terminal region of the protein is partly responsible for the unique mode of repressor activation by transition metal ions. |
==About this Structure== | ==About this Structure== | ||
| - | 2TDX is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Corynebacterium_diphtheriae Corynebacterium diphtheriae] with <scene name='pdbligand=NI:'>NI</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. This structure | + | 2TDX is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Corynebacterium_diphtheriae Corynebacterium diphtheriae] with <scene name='pdbligand=NI:'>NI</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. This structure supersedes the now removed PDB entry 1TDX. Known structural/functional Sites: <scene name='pdbsite=NI1:Ancillary+Metal-Ion+Binding+Site+(1)'>NI1</scene> and <scene name='pdbsite=NI2:Primary+Metal-Ion+Binding+Site+(2)'>NI2</scene>. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2TDX OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Single protein]] | [[Category: Single protein]] | ||
[[Category: Ding, X.]] | [[Category: Ding, X.]] | ||
| - | [[Category: Murphy, J | + | [[Category: Murphy, J R.]] |
[[Category: Ringe, D.]] | [[Category: Ringe, D.]] | ||
[[Category: Schiering, N.]] | [[Category: Schiering, N.]] | ||
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[[Category: transcription regulation]] | [[Category: transcription regulation]] | ||
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 18:49:41 2008'' |
Revision as of 16:49, 21 February 2008
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DIPHTHERIA TOX REPRESSOR (C102D MUTANT) COMPLEXED WITH NICKEL
Overview
The virulent phenotype of the pathogenic bacterium Corynebacterium diphtheriae is conferred by diphtheria toxin, whose expression is an adaptive response to low concentrations of iron. The expression of the toxin gene (tox) is regulated by the repressor DtxR, which is activated by transition metal ions. X-ray crystal structures of DtxR with and without (apo-form) its coordinated transition metal ion have established the general architecture of the repressor, identified the location of the metal-binding sites, and revealed a metal-ion-triggered subunit-subunit 'caliper-like' conformational change. Here we report the three-dimensional crystal structure of the complex between a biologically active Ni(II)-bound DtxR(C102D) mutant, in which a cysteine is replaced by an aspartate at residue 102, and a 33-base-pair DNA segment containing the toxin operator toxO. This structure shows that DNA interacts with two dimeric repressor proteins bound to opposite sides of the tox operator. We propose that a metal-ion-induced helix-to-coil structural transition in the amino-terminal region of the protein is partly responsible for the unique mode of repressor activation by transition metal ions.
About this Structure
2TDX is a Single protein structure of sequence from Corynebacterium diphtheriae with as ligand. This structure supersedes the now removed PDB entry 1TDX. Known structural/functional Sites: and . Full crystallographic information is available from OCA.
Reference
Structure of the metal-ion-activated diphtheria toxin repressor/tox operator complex., White A, Ding X, vanderSpek JC, Murphy JR, Ringe D, Nature. 1998 Jul 30;394(6692):502-6. PMID:9697776
Page seeded by OCA on Thu Feb 21 18:49:41 2008
