View source for 1xa3


==Crystal structure of CaiB, a type III CoA transferase in carnitine metabolism==
<StructureSection load='1xa3' size='340' side='right'caption='[[1xa3]], [[Resolution|resolution]] 1.85&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1xa3]] 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=1XA3 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1XA3 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]] 1.85&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=BTB:2-[BIS-(2-HYDROXY-ETHYL)-AMINO]-2-HYDROXYMETHYL-PROPANE-1,3-DIOL'>BTB</scene>, <scene name='pdbligand=MSE:SELENOMETHIONINE'>MSE</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=1xa3 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1xa3 OCA], [https://pdbe.org/1xa3 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1xa3 RCSB], [https://www.ebi.ac.uk/pdbsum/1xa3 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1xa3 ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/CAIB_ECOLI CAIB_ECOLI] Catalyzes the reversible transfer of the CoA moiety from gamma-butyrobetainyl-CoA to L-carnitine to generate L-carnitinyl-CoA and gamma-butyrobetaine. Is also able to catalyze the reversible transfer of the CoA moiety from gamma-butyrobetainyl-CoA or L-carnitinyl-CoA to crotonobetaine to generate crotonobetainyl-CoA.<ref>PMID:11551212</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/xa/1xa3_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=1xa3 ConSurf].
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== Publication Abstract from PubMed ==
Carnitine is an important molecule in human metabolism, mainly because of its role in the transport of long-chain fatty acids across the inner mitochondrial membrane. Escherichia coli uses carnitine as a terminal electron acceptor during anaerobic metabolism. Bacteria present in our large intestine break down carnitine that is not absorbed in the small intestine. One part of this catabolic pathway is reversible and can be utilized for bioproduction of large amounts of stereochemically pure L-carnitine, which is used medically for the treatment of a variety of human diseases. Here, we present the crystal structure of the E. coli protein CaiB, which is a member of the recently identified type-III coenzyme A (CoA) transferase family and catalyzes the transfer of the CoA moiety between gamma-butyrobetaine-CoA and carnitine forming carnityl-CoA and gamma-butyrobetaine. This is the first protein from the carnitine metabolic pathway to be structurally characterized. The structure of CaiB reveals a spectacular fold where two monomers are interlaced to form an interlocked dimer. A molecule of the crystallization buffer bis-(2-hydroxyethyl)imino-tris(hydroxymethyl)methane (bis-tris) is bound in a large pocket located primarily in the small domain, and we propose that this pocket constitutes the binding site for both substrate moieties participating in the CaiB transfer reaction. The binding of CoA to CaiB induces a domain movement that closes the active site of the protein. This is the first observation of a domain movement in the type-III CoA transferase family and can play an important role in coupling substrate binding to initiation of the catalytic reaction.

Crystal structure of CaiB, a type-III CoA transferase in carnitine metabolism.,Stenmark P, Gurmu D, Nordlund P Biochemistry. 2004 Nov 9;43(44):13996-4003. PMID:15518548<ref>PMID:15518548</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: Escherichia coli]]
[[Category: Large Structures]]
[[Category: Gurmu D]]
[[Category: Nordlund P]]
[[Category: Stenmark P]]