View source for 3md9


==Structure of apo form of a periplasmic heme binding protein==
<StructureSection load='3md9' size='340' side='right'caption='[[3md9]], [[Resolution|resolution]] 1.50&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[3md9]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Yersinia_pestis Yersinia pestis]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=3MD9 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=3MD9 FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 1.5&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=BR:BROMIDE+ION'>BR</scene>, <scene name='pdbligand=GOL:GLYCEROL'>GOL</scene>, <scene name='pdbligand=SO4:SULFATE+ION'>SO4</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=3md9 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=3md9 OCA], [https://pdbe.org/3md9 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=3md9 RCSB], [https://www.ebi.ac.uk/pdbsum/3md9 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=3md9 ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/HMUT_YERPE HMUT_YERPE] Part of the binding-protein-dependent transport system for hemin.
== 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/md/3md9_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=3md9 ConSurf].
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== Publication Abstract from PubMed ==
The periplasmic binding protein HmuT from Yersinia pestis (YpHmuT) is a component of the heme uptake locus hmu and delivers bound hemin to the inner-membrane-localized, ATP-binding cassette (ABC) transporter HmuUV for translocation into the cytoplasm. The mechanism of this process, heme transport across the inner membrane of pathogenic bacteria, is currently insufficiently understood at the molecular level. Here we describe the crystal structures of the substrate-free and heme-bound states of YpHmuT, revealing two lobes with a central binding cleft. Superposition of the apo and holo states reveals a minor tilting motion of the lobes surrounding concomitant with heme binding. Unexpectedly, YpHmuT binds two stacked hemes in a central binding cleft that is larger than those of the homologous periplasmic heme-binding proteins ShuT and PhuT, both of which bind only one heme. The hemes bound to YpHmuT are coordinated via a tyrosine side chain that contacts the Fe atom of one heme and a histidine that contacts the Fe atom of the other heme. The coordinating histidine is only conserved in a subset of heme substrate binding proteins, suggesting that its presence predicts the ability to bind two heme molecules simultaneously. The structural data are supported by spectroscopic binding studies performed in solution, where up to two hemes can bind to YpHmuT. Isothermal titration calorimetry suggests that the two hemes are bound in discrete, sequential steps and with dissociation constants (K(D)) of approximately 0.29 and approximately 29 nM, which is similar to the affinities observed in other bacterial substrate binding proteins. Our findings suggest that the cognate ABC transporter HmuUV may simultaneously translocate two hemes per reaction cycle.

Two Stacked Heme Molecules in the Binding Pocket of the Periplasmic Heme-Binding Protein HmuT from Yersinia pestis.,Mattle D, Zeltina A, Woo JS, Goetz BA, Locher KP J Mol Biol. 2010 Oct 1. PMID:20888343<ref>PMID:20888343</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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<div class="pdbe-citations 3md9" style="background-color:#fffaf0;"></div>
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Yersinia pestis]]
[[Category: Goetz BA]]
[[Category: Locher KP]]
[[Category: Mattle D]]