1s98: Difference between revisions

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New page: left|200px<br /><applet load="1s98" size="450" color="white" frame="true" align="right" spinBox="true" caption="1s98, resolution 2.30Å" /> '''E.coli IscA crystal ...
 
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[[Image:1s98.gif|left|200px]]<br /><applet load="1s98" size="450" color="white" frame="true" align="right" spinBox="true"
caption="1s98, resolution 2.30&Aring;" />
'''E.coli IscA crystal structure to 2.3 A'''<br />


==Overview==
==E.coli IscA crystal structure to 2.3 A==
IscA, an 11 kDa member of the hesB family of proteins, binds iron and, [2Fe-2S] clusters, and participates in the biosynthesis of iron-sulfur, proteins. We report the crystal structure of the apo-protein form of IscA, from Escherichia coli to a resolution of 2.3A. The crystals belong to the, space group P3(2)21 and have unit cell dimensions a=b=66.104 A, c=150.167, A (alpha=beta=90 degrees, gamma=120 degrees ). The structure was solved, using single-wavelength anomalous dispersion (SAD) phasing of a, selenomethionyl derivative, and the IscA model was refined to R=21.4%, (Rfree=25.4%). IscA exists as an (alpha1alpha2)2 homotetramer with the, (alpha1alpha2) dimer comprising the asymmetric unit. Cys35, implicated in, Fe-S cluster assembly, is located in a central cavity formed at the, tetramer interface with the gamma-sulfur atoms of residues from the alpha1, and alpha2' monomers (and alpha1'alpha2) positioned close to one another, (approximately equal 7 A). C-terminal residues 99-107 are disordered, and, the exact positions of Cys99 and Cys101 could not be determined. However, computer modeling of C-terminal residues in the tetramer suggests that, Cys99 and Cys101 in the alpha1 monomer and those of the alpha1' monomer, (or alpha2 and alpha2') are positioned sufficiently close to coordinate, [2Fe-2S] clusters between the two dimers, whereas this is not possible, within the (alpha1alpha2) or (alpha1'alpha2') dimer. This symmetrical, arrangement allows for binding of two [2Fe-2S] clusters on opposite sides, of the tetramer. Modeling further reveals that Cys101 is positioned, sufficiently close to Cys35 to allow Cys35 to participate in cluster, assembly, formation, or transfer.
<StructureSection load='1s98' size='340' side='right'caption='[[1s98]], [[Resolution|resolution]] 2.30&Aring;' scene=''>
 
== Structural highlights ==
==About this Structure==
<table><tr><td colspan='2'>[[1s98]] is a 2 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=1S98 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1S98 FirstGlance]. <br>
1S98 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli]. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1S98 OCA].  
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 2.3&#8491;</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=1s98 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1s98 OCA], [https://pdbe.org/1s98 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1s98 RCSB], [https://www.ebi.ac.uk/pdbsum/1s98 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1s98 ProSAT]</span></td></tr>
==Reference==
</table>
Crystal structure of IscA, an iron-sulfur cluster assembly protein from Escherichia coli., Cupp-Vickery JR, Silberg JJ, Ta DT, Vickery LE, J Mol Biol. 2004 Apr 16;338(1):127-37. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=15050828 15050828]
== Function ==
[https://www.uniprot.org/uniprot/ISCA_ECOLI ISCA_ECOLI] Is able to transfer iron-sulfur clusters to apo-ferredoxin. Multiple cycles of [2Fe2S] cluster formation and transfer are observed, suggesting that IscA acts catalytically. Recruits intracellular free iron so as to provide iron for the assembly of transient iron-sulfur cluster in IscU in the presence of IscS, L-cysteine and the thioredoxin reductase system TrxA/TrxB.[HAMAP-Rule:MF_01429]
== 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/s9/1s98_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=1s98 ConSurf].
<div style="clear:both"></div>
__TOC__
</StructureSection>
[[Category: Escherichia coli]]
[[Category: Escherichia coli]]
[[Category: Single protein]]
[[Category: Large Structures]]
[[Category: Cupp-Vickery, J.R.]]
[[Category: Cupp-Vickery JR]]
[[Category: Silberg, J.J.]]
[[Category: Silberg JJ]]
[[Category: Ta, D.T.]]
[[Category: Ta DT]]
[[Category: Vickery, L.E.]]
[[Category: Vickery LE]]
[[Category: fe-s cluster]]
[[Category: iron]]
[[Category: isc]]
[[Category: isca]]
[[Category: sulfur]]
 
''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Wed Nov 21 02:12:42 2007''

Latest revision as of 08:28, 14 February 2024

E.coli IscA crystal structure to 2.3 A

1s98, resolution 2.30Å

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