1bjz
From Proteopedia
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- | {{Seed}} | ||
- | [[Image:1bjz.png|left|200px]] | ||
- | < | + | ==TETRACYCLINE CHELATED MG2+-ION INITIATES HELIX UNWINDING FOR TET REPRESSOR INDUCTION== |
- | + | <StructureSection load='1bjz' size='340' side='right'caption='[[1bjz]], [[Resolution|resolution]] 2.20Å' scene=''> | |
- | You may | + | == Structural highlights == |
- | + | <table><tr><td colspan='2'>[[1bjz]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1BJZ OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1BJZ FirstGlance]. <br> | |
- | or | + | </td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 2.2Å</td></tr> |
- | - | + | <tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=1bjz FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1bjz OCA], [https://pdbe.org/1bjz PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1bjz RCSB], [https://www.ebi.ac.uk/pdbsum/1bjz PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1bjz ProSAT]</span></td></tr> |
- | + | </table> | |
+ | == Function == | ||
+ | [https://www.uniprot.org/uniprot/TETR4_ECOLX TETR4_ECOLX] TetR is the repressor of the tetracycline resistance element; its N-terminal region forms a helix-turn-helix structure and binds DNA. Binding of tetracycline to TetR reduces the repressor affinity for the tetracycline resistance gene (tetA) promoter operator sites. | ||
+ | == Evolutionary Conservation == | ||
+ | [[Image:Consurf_key_small.gif|200px|right]] | ||
+ | Check<jmol> | ||
+ | <jmolCheckbox> | ||
+ | <scriptWhenChecked>; select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/bj/1bjz_consurf.spt"</scriptWhenChecked> | ||
+ | <scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview01.spt</scriptWhenUnchecked> | ||
+ | <text>to colour the structure by Evolutionary Conservation</text> | ||
+ | </jmolCheckbox> | ||
+ | </jmol>, as determined by [http://consurfdb.tau.ac.il/ ConSurfDB]. You may read the [[Conservation%2C_Evolutionary|explanation]] of the method and the full data available from [http://bental.tau.ac.il/new_ConSurfDB/main_output.php?pdb_ID=1bjz ConSurf]. | ||
+ | <div style="clear:both"></div> | ||
+ | <div style="background-color:#fffaf0;"> | ||
+ | == Publication Abstract from PubMed == | ||
+ | The homodimeric tetracycline repressor (TetR) regulates resistance to the antibiotic tetracycline at the transcriptional level. TetR binds in the absence of Tc to palindromic operator sequences utilizing two helix-turn-helix (HTH) motifs. If the tetracycline-Mg2+ complex [MgTc]+ enters two identical binding tunnels buried within the TetR homodimer, a conformational change takes place, and the induced [TetR/[MgTc]+]2 complex releases operator DNA. To demonstrate the contribution of Mg2+ to [MgTc]+ binding and TetR induction, the Mg2+ concentration in the induced TetR homodimer was progressively reduced by addition of EDTA, resulting in two X-ray crystal structures of Mg2+-free and half-occupied TetR(D). Tc remains bound to the [MgTc]+-binding sites, despite the complete or partial absence of Mg2+. Together with inducer-free TetR(D), the structures were refined to between 2.2 and 2.7 A resolution and compared with fully induced TetR(D) in complex with two [MgTc]+. Each inducer binding tunnel has three constituent parts, one hydrophobic and two hydrophilic ones. One of the hydrophilic contact areas binds Tc by hydrogen bonding; the hydrophobic region correctly positions Tc and partially closes the entrance to the binding tunnel; the second hydrophilic region coordinates Mg2+, transduces the induction signal, and completes the process of closing the tunnel entrance. Tc confers binding specificity to TetR while Mg2+ is primarily responsible for induction: After binding to the imidazole Nepsilon of His100, Mg2+ is octahedrally coordinated to the 1,3-ketoenolate group of Tc and to three water molecules. One of these waters forms a hydrogen bond to the hydroxyl group Ogamma of Thr103. The induced 2.5 A movement of Thr103 results in the partial unwinding of helix alpha6, associated with a lateral shift of helices alpha4 and alpha9. They simultaneously close the tunnel entrance and cause the DNA-binding domains to adopt a nonbinding conformation, leading to release of operator DNA and expression of the genes responsible for resistance. | ||
- | + | Tetracycline-chelated Mg2+ ion initiates helix unwinding in Tet repressor induction.,Orth P, Saenger W, Hinrichs W Biochemistry. 1999 Jan 5;38(1):191-8. PMID:9890898<ref>PMID:9890898</ref> | |
+ | From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br> | ||
+ | </div> | ||
+ | <div class="pdbe-citations 1bjz" style="background-color:#fffaf0;"></div> | ||
- | + | ==See Also== | |
- | + | *[[Tetracycline repressor protein 3D structures|Tetracycline repressor protein 3D structures]] | |
- | + | == References == | |
- | + | <references/> | |
- | + | __TOC__ | |
- | + | </StructureSection> | |
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[[Category: Escherichia coli]] | [[Category: Escherichia coli]] | ||
- | [[Category: | + | [[Category: Large Structures]] |
- | [[Category: Hinrichs | + | [[Category: Hinrichs W]] |
- | [[Category: Orth | + | [[Category: Orth P]] |
- | [[Category: Saenger | + | [[Category: Saenger W]] |
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Current revision
TETRACYCLINE CHELATED MG2+-ION INITIATES HELIX UNWINDING FOR TET REPRESSOR INDUCTION
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