View source for 1xk7


==Crystal Structure- C2 form- of Escherichia coli Crotonobetainyl-CoA: carnitine CoA transferase (CaiB)==
<StructureSection load='1xk7' size='340' side='right'caption='[[1xk7]], [[Resolution|resolution]] 1.60&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1xk7]] is a 3 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=1XK7 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1XK7 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]] 1.6&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=MSE:SELENOMETHIONINE'>MSE</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=1xk7 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1xk7 OCA], [https://pdbe.org/1xk7 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1xk7 RCSB], [https://www.ebi.ac.uk/pdbsum/1xk7 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1xk7 ProSAT], [https://www.topsan.org/Proteins/BSGI/1xk7 TOPSAN]</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/xk/1xk7_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=1xk7 ConSurf].
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== Publication Abstract from PubMed ==
L-Carnitine (R-[-]-3-hydroxy-4-trimethylaminobutyrate) is found in both eukaryotic and prokaryotic cells and participates in diverse processes including long-chain fatty-acid transport and osmoprotection. The enzyme crotonobetainyl/gamma-butyrobetainyl-CoA:carnitine CoA-transferase (CaiB; E.C. 2.8.3.-) catalyzes the first step in carnitine metabolism, leading to the final product gamma-butyrobetaine. The crystal structures of Escherichia coli apo-CaiB, as well as its Asp169Ala mutant bound to CoA and to carnitinyl-CoA, have been determined and refined to 1.6, 2.4, and 2.4 A resolution, respectively. CaiB is composed of two identical circular chains that together form an intertwined dimer. Each monomer consists of a large domain, containing a Rossmann fold, and a small domain. The monomer and dimer resemble those of formyl-CoA transferase from Oxalobacter formigenes, as well as E. coli YfdW, a putative type-III CoA transferase of unknown function. The CoA cofactor-binding site is formed at the interface of the large domain of one monomer and the small domain from the second monomer. Most of the protein-CoA interactions are formed with the Rossmann fold domain. While the location of cofactor binding is similar in the three proteins, the specific CoA-protein interactions vary somewhat between CaiB, formyl-CoA transferase, and YfdW. CoA binding results in a change in the relative positions of the large and small domains compared with apo-CaiB. The observed carnitinyl-CoA product in crystals of the CaiB Asp169Ala mutant cocrystallized with crotonoyl-CoA and carnitine could result from (i) a catalytic mechanism involving a ternary enzyme-substrate complex, independent of a covalent anhydride intermediate with Asp169, (ii) a spontaneous reaction of the substrates in solution, followed by binding to the enzyme, or (iii) an involvement of another residue substituting functionally for Asp169, such as Glu23.

Crystal structure of Escherichia coli crotonobetainyl-CoA: carnitine CoA-transferase (CaiB) and its complexes with CoA and carnitinyl-CoA.,Rangarajan ES, Li Y, Iannuzzi P, Cygler M, Matte A Biochemistry. 2005 Apr 19;44(15):5728-38. PMID:15823031<ref>PMID:15823031</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: Cygler M]]
[[Category: Iannuzzi P]]
[[Category: Li Y]]
[[Category: Matte A]]
[[Category: Rangarajan ES]]