View source for 2cn4


==The crystal structure of the secreted dimeric form of the hemophore HasA reveals a domain swapping with an exchanged heme ligand==
<StructureSection load='2cn4' size='340' side='right'caption='[[2cn4]], [[Resolution|resolution]] 2.30&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[2cn4]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Serratia_marcescens Serratia marcescens]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2CN4 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=2CN4 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]] 2.3&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=HEM:PROTOPORPHYRIN+IX+CONTAINING+FE'>HEM</scene>, <scene name='pdbligand=PO4:PHOSPHATE+ION'>PO4</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=2cn4 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=2cn4 OCA], [https://pdbe.org/2cn4 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=2cn4 RCSB], [https://www.ebi.ac.uk/pdbsum/2cn4 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=2cn4 ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/HASA_SERMA HASA_SERMA] Can bind free heme and also acquire it from hemoglobin. Conveys heme from hemoglobin to the HasR receptor which releases it into the bacterium. HasR alone can take up heme but the synergy between HasA and HasR increases heme uptake 100-fold.<ref>PMID:7937909</ref> <ref>PMID:9171402</ref> 
== 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/cn/2cn4_consurf.spt"</scriptWhenChecked>
    <scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview03.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=2cn4 ConSurf].
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== Publication Abstract from PubMed ==
To satisfy their iron needs, several Gram-negative bacteria use a heme uptake system involving an extracellular heme-binding protein called hemophore. The function of the hemophore is to acquire free or hemoprotein-bound heme and to transfer it to HasR, its specific outer membrane receptor, by protein-protein interaction. The hemophore HasA secreted by Serratia marcescens, an opportunistic pathogen, was the first to be identified and is now very well characterized. HasA is a monomer that binds one b heme with strong affinity. The heme in HasA is highly exposed to solvent and coordinated by an unusual pair of ligands, a histidine and a tyrosine. Here, we report the identification, the characterization and the X-ray structure of a dimeric form of HasA from S. marcescens: DHasA. We show that both monomeric and dimeric forms are secreted in iron deficient conditions by S. marcescens. The crystal structure of DHasA reveals that it is a domain swapped dimer. The overall structure of each monomeric subunit of DHasA is very similar to that of HasA but formed by parts coming from the two different polypeptide chains, involving one of the heme ligands. Consequently DHasA binds two heme molecules by residues coming from both polypeptide chains. We show here that, while DHasA can bind two heme molecules, it is not able to deliver them to the receptor HasR. However, DHasA can efficiently transfer its heme to the monomeric form that, in turn, delivers it to HasR. We assume that DHasA can function as a heme reservoir in the hemophore system.

The crystal structure of the secreted dimeric form of the hemophore HasA reveals a domain swapping with an exchanged heme ligand.,Czjzek M, Letoffe S, Wandersman C, Delepierre M, Lecroisey A, Izadi-Pruneyre N J Mol Biol. 2007 Jan 26;365(4):1176-86. Epub 2006 Oct 25. PMID:17113104<ref>PMID:17113104</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Serratia marcescens]]
[[Category: Czjzek M]]
[[Category: Delepierre M]]
[[Category: Izadi-Pruneyre N]]
[[Category: Lecroisey A]]
[[Category: Letoffe S]]
[[Category: Wandersman C]]