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'''NMR structure of the redox switch domain of the E. coli Hsp33'''<br />


==Overview==
==NMR structure of the redox switch domain of the E. coli Hsp33==
The Escherichia coli chaperone Hsp33 contains a C-terminal zinc-binding, domain that modulates activity by a so-called "redox switch". The oxidized, form in the absence of zinc is active, while the reduced form in the, presence of zinc is inactive. X-ray crystal structures of Hsp33 invariably, omit details of the C-terminal domain, which is truncated in protein, constructs that are capable of forming crystals. We report the solution, structure of a recombinant 61-residue protein containing the zinc-binding, domain (residues 227-287) of Hsp33, in the presence of stoichiometric, amounts of Zn2+. The zinc-bound protein is well folded, and forms a novel, structure unlike other published zinc-binding domains. The structure, consists of two helices at right-angles to each other, a two-stranded, B-hairpin and a third helix at the C terminus. The zinc site comprises the, side-chains of the conserved cysteine residues 232, 234, 262 and 265, and, connects a short sequence before the first helix with the tight turn in, the middle of the B-hairpin. The structure of the C-terminal zinc-binding, domain suggests a mechanism for the operation of the redox switch: loss of, the bound zinc ion disrupts the folded structure, allowing the ligand, cysteine residues to be oxidized, probably to disulfide bonds. The, observation that the C-terminal domain is poorly structured in the active, oxidized form suggests that the loss of zinc and unfolding of the domain, precedes the oxidation of the thiolate groups of the cysteine residues, since the formation of disulfides between distant parts of the domain, sequence would presumably promote the formation of stable, three-dimensional structure in the oxidized form.Hsp33 provides an example, of a redox signaling system that utilizes protein folding and unfolding, together with chemical modification for transduction of external stimuli, in this case oxidative stress, to activate the machinery of the cell that, is designed to deal with that stress.
<StructureSection load='1xjh' size='340' side='right'caption='[[1xjh]]' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1xjh]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli]. Full experimental information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1XJH OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1XJH FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">Solution NMR</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=ZN:ZINC+ION'>ZN</scene></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=1xjh FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1xjh OCA], [https://pdbe.org/1xjh PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1xjh RCSB], [https://www.ebi.ac.uk/pdbsum/1xjh PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1xjh ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/HSLO_ECOLI HSLO_ECOLI] Redox regulated molecular chaperone. Protects both thermally unfolding and oxidatively damaged proteins from irreversible aggregation. Plays an important role in the bacterial defense system toward oxidative stress.[HAMAP-Rule:MF_00117]
== 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/xj/1xjh_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=1xjh ConSurf].
<div style="clear:both"></div>
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
The Escherichia coli chaperone Hsp33 contains a C-terminal zinc-binding domain that modulates activity by a so-called "redox switch". The oxidized form in the absence of zinc is active, while the reduced form in the presence of zinc is inactive. X-ray crystal structures of Hsp33 invariably omit details of the C-terminal domain, which is truncated in protein constructs that are capable of forming crystals. We report the solution structure of a recombinant 61-residue protein containing the zinc-binding domain (residues 227-287) of Hsp33, in the presence of stoichiometric amounts of Zn2+. The zinc-bound protein is well folded, and forms a novel structure unlike other published zinc-binding domains. The structure consists of two helices at right-angles to each other, a two-stranded B-hairpin and a third helix at the C terminus. The zinc site comprises the side-chains of the conserved cysteine residues 232, 234, 262 and 265, and connects a short sequence before the first helix with the tight turn in the middle of the B-hairpin. The structure of the C-terminal zinc-binding domain suggests a mechanism for the operation of the redox switch: loss of the bound zinc ion disrupts the folded structure, allowing the ligand cysteine residues to be oxidized, probably to disulfide bonds. The observation that the C-terminal domain is poorly structured in the active oxidized form suggests that the loss of zinc and unfolding of the domain precedes the oxidation of the thiolate groups of the cysteine residues, since the formation of disulfides between distant parts of the domain sequence would presumably promote the formation of stable three-dimensional structure in the oxidized form.Hsp33 provides an example of a redox signaling system that utilizes protein folding and unfolding together with chemical modification for transduction of external stimuli, in this case oxidative stress, to activate the machinery of the cell that is designed to deal with that stress.


==About this Structure==
The zinc-dependent redox switch domain of the chaperone Hsp33 has a novel fold.,Won HS, Low LY, Guzman RD, Martinez-Yamout M, Jakob U, Dyson HJ J Mol Biol. 2004 Aug 20;341(4):893-9. PMID:15328602<ref>PMID:15328602</ref>
1XJH is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli] with ZN as [http://en.wikipedia.org/wiki/ligand ligand]. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1XJH OCA].


==Reference==
From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
The zinc-dependent redox switch domain of the chaperone Hsp33 has a novel fold., Won HS, Low LY, Guzman RD, Martinez-Yamout M, Jakob U, Dyson HJ, J Mol Biol. 2004 Aug 20;341(4):893-9. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=15328602 15328602]
</div>
<div class="pdbe-citations 1xjh" style="background-color:#fffaf0;"></div>
 
==See Also==
*[[Heat Shock Protein structures|Heat Shock Protein structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Escherichia coli]]
[[Category: Escherichia coli]]
[[Category: Single protein]]
[[Category: Large Structures]]
[[Category: Dyson, H.J.]]
[[Category: De Guzman RN]]
[[Category: Guzman, R.N.De.]]
[[Category: Dyson HJ]]
[[Category: Jakob, U.]]
[[Category: Jakob U]]
[[Category: Low, L.Y.]]
[[Category: Low LY]]
[[Category: Martinez-Yamout, M.A.]]
[[Category: Martinez-Yamout MA]]
[[Category: Won, H.S.]]
[[Category: Won HS]]
[[Category: ZN]]
[[Category: four cysteins coordinating zinc]]
[[Category: redox-switch domain]]
[[Category: zinc-binding domain]]
 
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