View source for 1ogb


==Chitinase b from Serratia marcescens mutant D142N==
<StructureSection load='1ogb' size='340' side='right'caption='[[1ogb]], [[Resolution|resolution]] 1.85&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1ogb]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Serratia_marcescens Serratia marcescens]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1OGB OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1OGB 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=GOL:GLYCEROL'>GOL</scene>, <scene name='pdbligand=SO4:SULFATE+ION'>SO4</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=1ogb FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1ogb OCA], [https://pdbe.org/1ogb PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1ogb RCSB], [https://www.ebi.ac.uk/pdbsum/1ogb PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1ogb ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/CHIB_SERMA CHIB_SERMA] 
== 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/og/1ogb_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=1ogb ConSurf].
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== Publication Abstract from PubMed ==
Catalysis by ChiB, a family 18 chitinase from Serratia marcescens, involves a conformational change of Asp142 which is part of a characteristic D(140)XD(142)XE(144) sequence motif. In the free enzyme Asp142 points towards Asp140, whereas it rotates towards the catalytic acid, Glu144, upon ligand binding. Mutation of Asp142 to Asn reduced k(cat) and affinity for allosamidin, a competitive inhibitor. The X-ray structure of the D142N mutant showed that Asn142 points towards Glu144 in the absence of a ligand. The active site also showed other structural adjustments (Tyr10, Ser93) that had previously been observed in the wild-type enzyme upon substrate binding. The X-ray structure of a complex of D142N with allosamidin, a pseudotrisaccharide competitive inhibitor, was essentially identical to that of the wild-type enzyme in complex with the same compound. Thus, the reduced allosamidin affinity in the mutant is not caused by structural changes but solely by the loss of electrostatic interactions with Asp142. The importance of electrostatics was further confirmed by the pH dependence of catalysis and allosamidin inhibition. The pH-dependent apparent affinities for allosamidin were not correlated with k(cat), indicating that it is probably better to view the inhibitor as a mimic of the oxazolinium ion reaction intermediate than as a transition state analogue.

Structure of the D142N mutant of the family 18 chitinase ChiB from Serratia marcescens and its complex with allosamidin.,Vaaje-Kolstad G, Houston DR, Rao FV, Peter MG, Synstad B, van Aalten DM, Eijsink VG Biochim Biophys Acta. 2004 Jan 14;1696(1):103-11. PMID:14726210<ref>PMID:14726210</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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<div class="pdbe-citations 1ogb" style="background-color:#fffaf0;"></div>

==See Also==
*[[Chitinase 3D structures|Chitinase 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Serratia marcescens]]
[[Category: Eijsink VGH]]
[[Category: Houston DR]]
[[Category: Peter MG]]
[[Category: Rao FV]]
[[Category: Synstad B]]
[[Category: Vaaje-Kolstad G]]
[[Category: Van Aalten DMF]]