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[[Image:1mul.gif|left|200px]]<br /><applet load="1mul" size="350" color="white" frame="true" align="right" spinBox="true"
caption="1mul, resolution 2.30&Aring;" />
'''Crystal structure of the E. coli HU alpha2 protein'''<br />


==Overview==
==Crystal structure of the E. coli HU alpha2 protein==
The Escherichia coli histone-like HU protein pool is composed of three dimeric forms: two homodimers, EcHUalpha(2) and EcHUbeta(2), and a heterodimer, EcHUalphabeta. The relative abundance of these dimeric forms varies during cell growth and in response to environmental changes, suggesting that each dimer plays different physiological roles. Here, differential scanning calorimetry and circular dichroism (CD) were used to study the thermal stability of the three E.coli HU dimers and show that each of them has its own thermodynamic signature. Unlike the other HU proteins studied so far, which melt through a single step (N(2)&lt;--&gt;2D), this present thermodynamic study shows that the three E.coli dimers melt according to a two-step mechanism (N(2)&lt;--&gt;I(2)&lt;--&gt;2D). The native dimer, N(2), melts partially into a dimeric intermediate, I(2), which in turn yields the unfolded monomers, D. In addition, the crystal structure of the EcHUalpha(2) dimer has been solved. Comparative thermodynamic and structural analysis between EcHUalpha(2) and the HU homodimer from Bacillus stearothermophilus suggests that the E.coli dimer is constituted by two subdomains of different energetic properties. The CD study indicates that the intermediate, I(2), corresponds to an HU dimer having partly lost its alpha-helices. The partially unfolded dimer I(2) is unable to complex with high-affinity, single-stranded break-containing DNA. These structural, thermodynamic and functional results suggest that the N(2)&lt;--&gt;I(2) equilibrium plays a central role in the physiology of E.coli HU. The I(2) molecular species seems to be the EcHUbeta(2) preferential conformation, possibly related to its role in the E.coli cold-shock adaptation. Besides, I(2) might be required in E.coli for the HU chain exchange, which allows the heterodimer formation from homodimers.
<StructureSection load='1mul' size='340' side='right'caption='[[1mul]], [[Resolution|resolution]] 2.30&Aring;' scene=''>
 
== Structural highlights ==
==About this Structure==
<table><tr><td colspan='2'>[[1mul]] 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=1MUL OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1MUL FirstGlance]. <br>
1MUL 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://oca.weizmann.ac.il/oca-bin/ocashort?id=1MUL 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=1mul FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1mul OCA], [https://pdbe.org/1mul PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1mul RCSB], [https://www.ebi.ac.uk/pdbsum/1mul PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1mul ProSAT]</span></td></tr>
==Reference==
</table>
Evidence of a thermal unfolding dimeric intermediate for the Escherichia coli histone-like HU proteins: thermodynamics and structure., Ramstein J, Hervouet N, Coste F, Zelwer C, Oberto J, Castaing B, J Mol Biol. 2003 Aug 1;331(1):101-21. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=12875839 12875839]
== Function ==
[https://www.uniprot.org/uniprot/DBHA_ECOLI DBHA_ECOLI] Histone-like DNA-binding protein which is capable of wrapping DNA to stabilize it, and thus to prevent its denaturation under extreme environmental conditions.
== 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/mu/1mul_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=1mul ConSurf].
<div style="clear:both"></div>
__TOC__
</StructureSection>
[[Category: Escherichia coli]]
[[Category: Escherichia coli]]
[[Category: Single protein]]
[[Category: Large Structures]]
[[Category: Castaing, B.]]
[[Category: Castaing B]]
[[Category: Coste, F.]]
[[Category: Coste F]]
[[Category: Hervouet, N.]]
[[Category: Hervouet N]]
[[Category: Oberto, J.]]
[[Category: Oberto J]]
[[Category: Ramstein, J.]]
[[Category: Ramstein J]]
[[Category: Zelwer, C.]]
[[Category: Zelwer C]]
[[Category: histone-like]]
 
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 13:59:10 2008''

Latest revision as of 16:27, 13 March 2024

Crystal structure of the E. coli HU alpha2 proteinCrystal structure of the E. coli HU alpha2 protein

Structural highlights

1mul is a 1 chain structure with sequence from Escherichia coli. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:X-ray diffraction, Resolution 2.3Å
Resources:FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

DBHA_ECOLI Histone-like DNA-binding protein which is capable of wrapping DNA to stabilize it, and thus to prevent its denaturation under extreme environmental conditions.

Evolutionary Conservation

Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.

1mul, resolution 2.30Å

Drag the structure with the mouse to rotate

Proteopedia Page Contributors and Editors (what is this?)Proteopedia Page Contributors and Editors (what is this?)

OCA
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