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1chk

From Proteopedia

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[[Image:1chk.gif|left|200px]]<br /><applet load="1chk" size="450" color="white" frame="true" align="right" spinBox="true"
 
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caption="1chk, resolution 2.40&Aring;" />
 
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'''STREPTOMYCES N174 CHITOSANASE PH5.5 298K'''<br />
 
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==Overview==
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==STREPTOMYCES N174 CHITOSANASE PH5.5 298K==
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We report the 2.4 A X-ray crystal structure of a protein with chitosan, endo-hydrolase activity isolated from Streptomyces N174. The structure was, solved using phases acquired by SIRAS from a two-site methyl mercury, derivative combined with solvent flattening and non-crystallographic, two-fold symmetry averaging, and refined to an R-factor of 18.5%. The, mostly alpha-helical fold reveals a structural core shared with several, classes of lysozyme and barley endochitinase, in spite of a lack of shared, sequence. Based on this structural similarity we postulate a putative, active site, mechanism of action and mode of substrate recognition. It, appears that Glu 22 acts as an acid and Asp 40 serves as a general base to, activate a water molecule for an SN2 attack on the glycosidic bond. A, series of amino-acid side chains and backbone carbonyl groups may bind the, polycationic chitosan substrate in a deep electronegative binding cleft.
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<StructureSection load='1chk' size='340' side='right'caption='[[1chk]], [[Resolution|resolution]] 2.40&Aring;' scene=''>
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== Structural highlights ==
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==About this Structure==
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<table><tr><td colspan='2'>[[1chk]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Streptomyces_sp._N174 Streptomyces sp. N174]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1CHK OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1CHK FirstGlance]. <br>
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1CHK is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Streptomyces_sp. Streptomyces sp.]. Known structural/functional Site: <scene name='pdbsite=CAT:Putative Catalytic Residues'>CAT</scene>. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1CHK OCA].
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</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 2.4&#8491;</td></tr>
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<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=1chk FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1chk OCA], [https://pdbe.org/1chk PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1chk RCSB], [https://www.ebi.ac.uk/pdbsum/1chk PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1chk ProSAT]</span></td></tr>
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==Reference==
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</table>
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X-ray structure of an anti-fungal chitosanase from streptomyces N174., Marcotte EM, Monzingo AF, Ernst SR, Brzezinski R, Robertus JD, Nat Struct Biol. 1996 Feb;3(2):155-62. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=8564542 8564542]
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== Function ==
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[[Category: Single protein]]
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[https://www.uniprot.org/uniprot/CHIS_STRSN CHIS_STRSN] Aids in the defense against invading fungal pathogens by degrading their cell wall chitosan.
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[[Category: Streptomyces sp.]]
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== Evolutionary Conservation ==
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[[Category: Marcotte, E.M.]]
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[[Image:Consurf_key_small.gif|200px|right]]
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[[Category: Robertus, J.D.]]
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Check<jmol>
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[[Category: anti-fungal protein]]
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<jmolCheckbox>
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[[Category: hydrolase]]
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<scriptWhenChecked>; select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/ch/1chk_consurf.spt"</scriptWhenChecked>
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[[Category: o-glycosyl]]
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<scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview01.spt</scriptWhenUnchecked>
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<text>to colour the structure by Evolutionary Conservation</text>
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''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Tue Dec 18 14:38:45 2007''
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</jmolCheckbox>
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</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=1chk ConSurf].
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<div style="clear:both"></div>
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__TOC__
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</StructureSection>
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[[Category: Large Structures]]
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[[Category: Streptomyces sp. N174]]
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[[Category: Marcotte EM]]
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[[Category: Robertus JD]]

Current revision

STREPTOMYCES N174 CHITOSANASE PH5.5 298K

PDB ID 1chk

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