View source for 3hbn


==Crystal structure PseG-UDP complex from Campylobacter jejuni==
<StructureSection load='3hbn' size='340' side='right'caption='[[3hbn]], [[Resolution|resolution]] 1.85&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[3hbn]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Campylobacter_jejuni_subsp._jejuni_NCTC_11168_=_ATCC_700819 Campylobacter jejuni subsp. jejuni NCTC 11168 = ATCC 700819]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=3HBN OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=3HBN 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=CL:CHLORIDE+ION'>CL</scene>, <scene name='pdbligand=GOL:GLYCEROL'>GOL</scene>, <scene name='pdbligand=MSE:SELENOMETHIONINE'>MSE</scene>, <scene name='pdbligand=UDP:URIDINE-5-DIPHOSPHATE'>UDP</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=3hbn FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=3hbn OCA], [https://pdbe.org/3hbn PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=3hbn RCSB], [https://www.ebi.ac.uk/pdbsum/3hbn PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=3hbn ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/PSEG_CAMJE PSEG_CAMJE] Nucleotide sugar hydrolase that catalyzes the fourth step in the biosynthesis of pseudaminic acid, a sialic-acid-like sugar that is used to modify flagellin. Mediates the removal of UDP from C-1 of UDP-2,4-diacetamido-2,4,6-trideoxy-beta-L-altropyranose forming 2,4-diacetamido-2,4,6-trideoxy-beta-L-altropyranose.<ref>PMID:16728396</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/hb/3hbn_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=3hbn ConSurf].
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== Publication Abstract from PubMed ==
Flagella of the bacteria Helicobacter pylori and Campylobacter jejuni are important virulence determinants, whose proper assembly and function are dependent upon glycosylation at multiple positions by sialic acid-like sugars, such as 5,7-diacetamido-3,5,7,9-tetradeoxy-l-glycero-l-manno-nonulosonic acid (pseudaminic acid (Pse)). The fourth enzymatic step in the pseudaminic acid pathway, the hydrolysis of UDP-2,4-diacetamido-2,4,6-trideoxy-beta-l-altropyranose to generate 2,4-diacetamido-2,4,6-trideoxy-l-altropyranose, is performed by the nucleotide sugar hydrolase PseG. To better understand the molecular basis of the PseG catalytic reaction, we have determined the crystal structures of C. jejuni PseG in apo-form and as a complex with its UDP product at 1.8 and 1.85 A resolution, respectively. In addition, molecular modeling was utilized to provide insight into the structure of the PseG-substrate complex. This modeling identifies a His(17)-coordinated water molecule as the putative nucleophile and suggests the UDP-sugar substrate adopts a twist-boat conformation upon binding to PseG, enhancing the exposure of the anomeric bond cleaved and favoring inversion at C-1. Furthermore, based on these structures a series of amino acid substitution derivatives were constructed, altering residues within the active site, and each was kinetically characterized to examine its contribution to PseG catalysis. In conjunction with structural comparisons, the almost complete inactivation of the PseG H17F and H17L derivatives suggests that His(17) functions as an active site base, thereby activating the nucleophilic water molecule for attack of the anomeric C-O bond of the UDP-sugar. As the PseG structure reveals similarity to those of glycosyltransferase family-28 members, in particular that of Escherichia coli MurG, these findings may also be of relevance for the mechanistic understanding of this important enzyme family.

Structural and functional analysis of Campylobacter jejuni PseG: a udp-sugar hydrolase from the pseudaminic acid biosynthetic pathway.,Rangarajan ES, Proteau A, Cui Q, Logan SM, Potetinova Z, Whitfield D, Purisima EO, Cygler M, Matte A, Sulea T, Schoenhofen IC J Biol Chem. 2009 Jul 31;284(31):20989-1000. Epub 2009 May 29. PMID:19483088<ref>PMID:19483088</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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==See Also==
*[[Aminotransferase 3D structures|Aminotransferase 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Campylobacter jejuni subsp. jejuni NCTC 11168 = ATCC 700819]]
[[Category: Large Structures]]
[[Category: Cygler M]]
[[Category: Matte A]]
[[Category: Proteau A]]
[[Category: Rangarajan ES]]
[[Category: Schoenhofen IC]]
[[Category: Sulea T]]