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| | ==Crystal structure of the salmonella effector SseK3== | | ==Crystal structure of the salmonella effector SseK3== |
| - | <StructureSection load='6eyr' size='340' side='right' caption='[[6eyr]], [[Resolution|resolution]] 2.20Å' scene=''> | + | <StructureSection load='6eyr' size='340' side='right'caption='[[6eyr]], [[Resolution|resolution]] 2.20Å' scene=''> |
| | == Structural highlights == | | == Structural highlights == |
| - | <table><tr><td colspan='2'>[[6eyr]] is a 2 chain structure with sequence from [http://en.wikipedia.org/wiki/Salts Salts]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=6EYR OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=6EYR FirstGlance]. <br> | + | <table><tr><td colspan='2'>[[6eyr]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Salmonella_enterica_subsp._enterica_serovar_Typhimurium_str._SL1344 Salmonella enterica subsp. enterica serovar Typhimurium str. SL1344]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=6EYR OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=6EYR FirstGlance]. <br> |
| - | </td></tr><tr id='NonStdRes'><td class="sblockLbl"><b>[[Non-Standard_Residue|NonStd Res:]]</b></td><td class="sblockDat"><scene name='pdbligand=MSE:SELENOMETHIONINE'>MSE</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]] 2.2Å</td></tr> |
| - | <tr id='gene'><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">sseK3, SL1344_1928 ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=216597 SALTS])</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'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=6eyr FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=6eyr OCA], [http://pdbe.org/6eyr PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=6eyr RCSB], [http://www.ebi.ac.uk/pdbsum/6eyr PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=6eyr 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=6eyr FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=6eyr OCA], [https://pdbe.org/6eyr PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=6eyr RCSB], [https://www.ebi.ac.uk/pdbsum/6eyr PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=6eyr ProSAT]</span></td></tr> |
| | </table> | | </table> |
| - | <div style="background-color:#fffaf0;">
| + | == Function == |
| - | == Publication Abstract from PubMed == | + | [https://www.uniprot.org/uniprot/A0A0H3NMP8_SALTS A0A0H3NMP8_SALTS] |
| - | The Salmonella secreted effector SseK3 translocates into host cells, targeting innate immune responses including NF-kappaB activation. SseK3 is a glycosyltransferase that transfers an N-acetylglucosamine (GlcNAc) moiety onto the guanidino group of a target arginine, modulating host cell function. However, a lack of structural information has precluded elucidation of the molecular mechanisms in arginine and GlcNAc selection. We report here the crystal structure of SseK3 in its apo form and in complex with hydrolysed UDP-GlcNAc. SseK3 possesses the typical glycosyltransferase type-A (GT-A)-family fold and the metal-coordinating DXD motif essential for ligand binding and enzymatic activity. Several conserved residues were essential for arginine-GlcNAcylation and SseK3-mediated inhibition of NF-kappaB activation. Isothermal titration calorimetry revealed SseK3's preference for manganese coordination. The pattern of interactions in the substrate-bound SseK3 structure explained the selection of the primary ligand. Structural re-arrangement of the C-terminal residues upon ligand binding was crucial for SseK3's catalytic activity and NMR analysis indicated that SseK3 has limited UDP-GlcNAc hydrolysis activity. The release of free N-acetyl alpha-D-glucosamine, and the presence of the same molecule in the SseK3 active site, classified it as a retaining glycosyltransferase. A glutamate residue in the active site suggested a double-inversion mechanism for the arginine N-glycosylation reaction. Homology models of SseK1, SseK2, and the Escherichia coli orthologue NleB1, reveal differences in the surface electrostatic charge distribution possibly accounting for their diverse activities. This first structure of a retaining GT-A arginine N-glycosyltransferase provides an important step towards a better understanding of this enzyme class and their roles as bacterial effectors.
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| - | Structural basis for the glycosyltransferase activity of the Salmonella effector SseK3.,Esposito D, Gunster RA, Martino L, El Omari K, Wagner A, Thurston TLM, Rittinger K J Biol Chem. 2018 Feb 15. pii: RA118.001796. doi: 10.1074/jbc.RA118.001796. PMID:29449376<ref>PMID:29449376</ref>
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| - | From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br>
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| - | </div>
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| - | <div class="pdbe-citations 6eyr" style="background-color:#fffaf0;"></div>
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| - | == References ==
| + | |
| - | <references/>
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| | __TOC__ | | __TOC__ |
| | </StructureSection> | | </StructureSection> |
| - | [[Category: Salts]] | + | [[Category: Large Structures]] |
| - | [[Category: Esposito, D]] | + | [[Category: Salmonella enterica subsp. enterica serovar Typhimurium str. SL1344]] |
| - | [[Category: Rittinger, K]] | + | [[Category: Esposito D]] |
| - | [[Category: Effector protein]] | + | [[Category: Rittinger K]] |
| - | [[Category: Glcnac]]
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| - | [[Category: Glycosyltransferase]]
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| - | [[Category: Toxin]]
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