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| | ==VexL: A periplasmic depolymerase provides new insight into ABC transporter-dependent secretion of bacterial capsular polysaccharides== | | ==VexL: A periplasmic depolymerase provides new insight into ABC transporter-dependent secretion of bacterial capsular polysaccharides== |
| - | <StructureSection load='6fi2' size='340' side='right' caption='[[6fi2]], [[Resolution|resolution]] 1.22Å' scene=''> | + | <StructureSection load='6fi2' size='340' side='right'caption='[[6fi2]], [[Resolution|resolution]] 1.22Å' scene=''> |
| | == Structural highlights == | | == Structural highlights == |
| - | <table><tr><td colspan='2'>[[6fi2]] is a 1 chain structure with sequence from [http://en.wikipedia.org/wiki/"alcaligenes_denitrificans"_leifson_and_hugh_1954 "alcaligenes denitrificans" leifson and hugh 1954]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=6FI2 OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=6FI2 FirstGlance]. <br> | + | <table><tr><td colspan='2'>[[6fi2]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Achromobacter_denitrificans Achromobacter denitrificans]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=6FI2 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=6FI2 FirstGlance]. <br> |
| - | </td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=DJB:alpha-D-2-N-acetyl-3-O-acetylgalactosaminuronic+acid'>DJB</scene>, <scene name='pdbligand=DJE:alpha-D-2-N-acetylgalactosaminuronic+acid'>DJE</scene>, <scene name='pdbligand=MLI:MALONATE+ION'>MLI</scene></td></tr> | + | </td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 1.22Å</td></tr> |
| - | <tr id='gene'><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">vexL ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=32002 "Alcaligenes denitrificans" Leifson and Hugh 1954])</td></tr>
| + | <tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=DJB:(2~{S},3~{R},4~{R},5~{R},6~{S})-5-acetamido-4-acetyloxy-3,6-bis(oxidanyl)oxane-2-carboxylic+acid'>DJB</scene>, <scene name='pdbligand=DJE:(2~{S},3~{R},4~{R},5~{R},6~{S})-5-acetamido-3,4,6-tris(oxidanyl)oxane-2-carboxylic+acid'>DJE</scene>, <scene name='pdbligand=MLI:MALONATE+ION'>MLI</scene></td></tr> |
| - | <tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=6fi2 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=6fi2 OCA], [http://pdbe.org/6fi2 PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=6fi2 RCSB], [http://www.ebi.ac.uk/pdbsum/6fi2 PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=6fi2 ProSAT]</span></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=6fi2 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=6fi2 OCA], [https://pdbe.org/6fi2 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=6fi2 RCSB], [https://www.ebi.ac.uk/pdbsum/6fi2 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=6fi2 ProSAT]</span></td></tr> |
| | </table> | | </table> |
| | + | == Function == |
| | + | [https://www.uniprot.org/uniprot/A0A160EBC2_ACHDE A0A160EBC2_ACHDE] |
| | <div style="background-color:#fffaf0;"> | | <div style="background-color:#fffaf0;"> |
| | == Publication Abstract from PubMed == | | == Publication Abstract from PubMed == |
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| | __TOC__ | | __TOC__ |
| | </StructureSection> | | </StructureSection> |
| - | [[Category: Alcaligenes denitrificans leifson and hugh 1954]] | + | [[Category: Achromobacter denitrificans]] |
| - | [[Category: Bas, A Le]] | + | [[Category: Large Structures]] |
| - | [[Category: Liston, S D]] | + | [[Category: Le Bas A]] |
| - | [[Category: McMahon, S A]]
| + | [[Category: Liston SD]] |
| - | [[Category: Naismith, J H]] | + | [[Category: McMahon SA]] |
| - | [[Category: Whitfield, C]] | + | [[Category: Naismith JH]] |
| - | [[Category: Carbohydrate biosynthesis]] | + | [[Category: Whitfield C]] |
| - | [[Category: Cell-surface]] | + | |
| - | [[Category: Lyase]]
| + | |
| - | [[Category: Pectate lyase]]
| + | |
| - | [[Category: Vi antigen]]
| + | |
| Structural highlights
Function
A0A160EBC2_ACHDE
Publication Abstract from PubMed
Capsules are surface layers of hydrated capsular polysaccharides (CPSs) produced by many bacteria. The human pathogen Salmonella enterica serovar Typhi produces "Vi antigen" CPS, which contributes to virulence. In a conserved strategy used by bacteria with diverse CPS structures, translocation of Vi antigen to the cell surface is driven by an ATP-binding cassette (ABC) transporter. These transporters are engaged in heterooligomeric complexes proposed to form an enclosed translocation conduit to the cell surface, allowing the transporter to power the entire process. We identified Vi antigen biosynthesis genetic loci in genera of the Burkholderiales, which are paradoxically distinguished from S. Typhi by encoding VexL, a predicted pectate lyase homolog. Biochemical analyses demonstrated that VexL is an unusual metal-independent endolyase with an acidic pH optimum that is specific for O-acetylated Vi antigen. A 1.22-A crystal structure of the VexL-Vi antigen complex revealed features which distinguish common secreted catabolic pectate lyases from periplasmic VexL, which participates in cell-surface assembly. VexL possesses a right-handed parallel beta-superhelix, of which one face forms an electropositive glycan-binding groove with an extensive hydrogen bonding network that includes Vi antigen acetyl groups and confers substrate specificity. VexL provided a probe to interrogate conserved features of the ABC transporter-dependent export model. When introduced into S Typhi, VexL localized to the periplasm and degraded Vi antigen. In contrast, a cytosolic derivative had no effect unless export was disrupted. These data provide evidence that CPS assembled in ABC transporter-dependent systems is actually exposed to the periplasm during envelope translocation.
Periplasmic depolymerase provides insight into ABC transporter-dependent secretion of bacterial capsular polysaccharides.,Liston SD, McMahon SA, Le Bas A, Suits MDL, Naismith JH, Whitfield C Proc Natl Acad Sci U S A. 2018 May 22;115(21):E4870-E4879. doi:, 10.1073/pnas.1801336115. Epub 2018 May 7. PMID:29735649[1]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Liston SD, McMahon SA, Le Bas A, Suits MDL, Naismith JH, Whitfield C. Periplasmic depolymerase provides insight into ABC transporter-dependent secretion of bacterial capsular polysaccharides. Proc Natl Acad Sci U S A. 2018 May 22;115(21):E4870-E4879. doi:, 10.1073/pnas.1801336115. Epub 2018 May 7. PMID:29735649 doi:http://dx.doi.org/10.1073/pnas.1801336115
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