View source for 1ofm


==CRYSTAL STRUCTURE OF CHONDROITINASE B COMPLEXED TO CHONDROITIN 4-SULFATE TETRASACCHARIDE==
<StructureSection load='1ofm' size='340' side='right'caption='[[1ofm]], [[Resolution|resolution]] 1.80&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1ofm]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Pedobacter_heparinus Pedobacter heparinus]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1OFM OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1OFM 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]] 1.8&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=ASG:2-DEOXY-2-ACETAMIDO-BETA-D-GALACTOSE-4-SULFATE'>ASG</scene>, <scene name='pdbligand=BDP:BETA-D-GLUCOPYRANURONIC+ACID'>BDP</scene>, <scene name='pdbligand=BGC:BETA-D-GLUCOSE'>BGC</scene>, <scene name='pdbligand=GCD:4,5-DEHYDRO-D-GLUCURONIC+ACID'>GCD</scene>, <scene name='pdbligand=GCU:D-GLUCURONIC+ACID'>GCU</scene>, <scene name='pdbligand=GLA:ALPHA+D-GALACTOSE'>GLA</scene>, <scene name='pdbligand=MAN:ALPHA-D-MANNOSE'>MAN</scene>, <scene name='pdbligand=MXZ:6-DEOXY-2-O-METHYL-ALPHA-L-GALACTOPYRANOSE'>MXZ</scene>, <scene name='pdbligand=PCA:PYROGLUTAMIC+ACID'>PCA</scene>, <scene name='pdbligand=RAM:ALPHA-L-RHAMNOSE'>RAM</scene>, <scene name='pdbligand=XYP:BETA-D-XYLOPYRANOSE'>XYP</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=1ofm FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1ofm OCA], [https://pdbe.org/1ofm PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1ofm RCSB], [https://www.ebi.ac.uk/pdbsum/1ofm PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1ofm ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/CSLB_PEDHD CSLB_PEDHD] Cleaves the glycosaminoglycan, dermatan sulfate.
== 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/of/1ofm_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=1ofm ConSurf].
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== Publication Abstract from PubMed ==
Chondroitinase B from Pedobacter heparinus is the only known enzyme strictly specific for dermatan sulfate and is a widely used enzymatic tool for the structural characterization of glycosaminoglycans. This beta-helical polysaccharide lyase belongs to family PL-6 and cleaves the beta(1,4) linkage of dermatan sulfate in a random manner, yielding 4,5-unsaturated dermatan sulfate disaccharides as the product. The previously reported structure of its complex with a dermatan sulfate disaccharide product identified the -1 and -2 subsites of the catalytic groove. We present here the structure of chondroitinase B complexed with several dermatan sulfate and chondroitin sulfate oligosaccharides. In particular, the soaking of chondroitinase B crystals with a dermatan sulfate hexasaccharide results in a complex with two dermatan sulfate disaccharide reaction products, enabling the identification of the +2 and +1 subsites. Unexpectedly, this structure revealed the presence of a calcium ion coordinated by sequence-conserved acidic residues and by the carboxyl group of the l-iduronic acid at the +1 subsite. Kinetic and site-directed mutagenesis experiments have subsequently demonstrated that chondroitinase B absolutely requires calcium for its activity, indicating that the protein-Ca(2+)-oligosaccharide complex is functionally relevant. Modeling of an intact tetrasaccharide in the active site of chondroitinase B provided a better understanding of substrate specificity and the role of Ca(2+) in enzymatic activity. Given these results, we propose that the Ca(2+) ion neutralizes the carboxyl moiety of the l-iduronic acid at the cleavage site, whereas the conserved residues Lys-250 and Arg-271 act as Bronsted base and acid, respectively, in the lytic degradation of dermatan sulfate by chondroitinase B.

The structure of chondroitin B lyase complexed with glycosaminoglycan oligosaccharides unravels a calcium-dependent catalytic machinery.,Michel G, Pojasek K, Li Y, Sulea T, Linhardt RJ, Raman R, Prabhakar V, Sasisekharan R, Cygler M J Biol Chem. 2004 Jul 30;279(31):32882-96. Epub 2004 May 21. PMID:15155751<ref>PMID:15155751</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Pedobacter heparinus]]
[[Category: Cygler M]]
[[Category: Michel G]]