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| [[Image:2r5o.jpg|left|200px]]<br /><applet load="2r5o" size="350" color="white" frame="true" align="right" spinBox="true"
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| caption="2r5o, resolution 1.300Å" />
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| '''Crystal structure of the C-terminal domain of wzt'''<br />
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| ==Overview== | | ==Crystal structure of the C-terminal domain of wzt== |
| ATP-binding-cassette (ABC) transporters are responsible for the export of a wide variety of cell-surface glycoconjugates in both Gram-positive and Gram-negative bacteria. These include the O-antigenic polysaccharide (O-PS) portion of lipopolysaccharide, a crucial virulence determinant in Gram-negative pathogens. O-PSs are synthesized by one of two fundamentally different pathways. Escherichia coli O serotypes O8 and O9a provide the prototype systems for studying O-PS export via ABC transporters. The transporter is composed of the transmembrane component Wzm and the nucleotide-binding component Wzt. Although the N-terminal domain of Wzt is a conventional ABC protein, the C-terminal domain of Wzt (C-Wzt) is a unique structural element that determines the specificity of the transporter for either the O8 or O9a O-PS. We show here that the two domains of Wzt can function when expressed as separate polypeptides; both are essential for export. In vitro, C-Wzt binds its cognate O-PS by recognizing a residue located at the nonreducing end of the polymer. The crystal structure of C-Wzt(O9a) is reported here and reveals a beta sandwich with an immunoglobulin-like topology that contains the O-PS-binding pocket. Substrate interactions with nucleotide-binding domains have been demonstrated in an ABC exporter previously. However, to our knowledge substrate binding by a discrete, cytoplasmic accessory domain in an extended nucleotide-binding domain polypeptide has not previously been demonstrated. Elucidation of the substrate-recognition system involved in O-PS export provides insight into the mechanism that coordinates polymer biosynthesis, termination, and export.
| | <StructureSection load='2r5o' size='340' side='right'caption='[[2r5o]], [[Resolution|resolution]] 1.30Å' scene=''> |
| | | == Structural highlights == |
| ==About this Structure== | | <table><tr><td colspan='2'>[[2r5o]] 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=2R5O OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=2R5O FirstGlance]. <br> |
| 2R5O is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli] with <scene name='pdbligand=CL:'>CL</scene>, <scene name='pdbligand=NA:'>NA</scene> and <scene name='pdbligand=PG4:'>PG4</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2R5O 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]] 1.3Å</td></tr> |
| | | <tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=CL:CHLORIDE+ION'>CL</scene>, <scene name='pdbligand=NA:SODIUM+ION'>NA</scene>, <scene name='pdbligand=PG4:TETRAETHYLENE+GLYCOL'>PG4</scene></td></tr> |
| ==Reference== | | <tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=2r5o FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=2r5o OCA], [https://pdbe.org/2r5o PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=2r5o RCSB], [https://www.ebi.ac.uk/pdbsum/2r5o PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=2r5o ProSAT]</span></td></tr> |
| Substrate binding by a bacterial ABC transporter involved in polysaccharide export., Cuthbertson L, Kimber MS, Whitfield C, Proc Natl Acad Sci U S A. 2007 Dec 4;104(49):19529-34. Epub 2007 Nov 21. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=18032609 18032609]
| | </table> |
| | == Function == |
| | [https://www.uniprot.org/uniprot/Q47591_ECOLX Q47591_ECOLX] |
| | == 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/r5/2r5o_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=2r5o ConSurf]. |
| | <div style="clear:both"></div> |
| | __TOC__ |
| | </StructureSection> |
| [[Category: Escherichia coli]] | | [[Category: Escherichia coli]] |
| [[Category: Single protein]] | | [[Category: Large Structures]] |
| [[Category: Cuthbertson, L.]] | | [[Category: Cuthbertson L]] |
| [[Category: Kimber, M S.]] | | [[Category: Kimber MS]] |
| [[Category: Whitfield, C.]] | | [[Category: Whitfield C]] |
| [[Category: CL]]
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| [[Category: NA]]
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| [[Category: PG4]]
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| [[Category: abc transporter]]
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| [[Category: atp-binding]]
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| [[Category: carbohydrate binding]]
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| [[Category: domain swapping]]
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| [[Category: immunoglobulin fold]]
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| [[Category: nucleotide-binding]]
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| [[Category: o antigen export]]
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| [[Category: transport protein]]
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| ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 18:44:50 2008''
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