1chk

<table><tr><td colspan='2'>[[1chk]] is a 2 chain structure. 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>

</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=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>

[[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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== Publication Abstract from PubMed ==

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.

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:8564542<ref>PMID:8564542</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 1chk" style="background-color:#fffaf0;"></div>

== References ==

<references/>

[[Category: Marcotte, E M]]

[[Category: Robertus, J D]]

[[Category: Anti-fungal protein]]

[[Category: O-glycosyl]]