View source for 4wqq


==Structure of EPNH mutant of CEL-I==
<StructureSection load='4wqq' size='340' side='right'caption='[[4wqq]], [[Resolution|resolution]] 1.70&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[4wqq]] is a 4 chain structure with sequence from [https://en.wikipedia.org/wiki/Cucumaria_echinata Cucumaria echinata]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=4WQQ OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=4WQQ 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]] 1.7&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=CA:CALCIUM+ION'>CA</scene>, <scene name='pdbligand=MAN:ALPHA-D-MANNOSE'>MAN</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=4wqq FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4wqq OCA], [https://pdbe.org/4wqq PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=4wqq RCSB], [https://www.ebi.ac.uk/pdbsum/4wqq PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=4wqq ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/Q7M462_CUCEC Q7M462_CUCEC] 
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
BACKGROUND: CEL-I is a galactose/N-acetylgalactosamine-specific C-type lectin isolated from the sea cucumber Cucumaria echinata. Its carbohydrate-binding site contains a QPD (Gln-Pro-Asp) motif, which is generally recognized as the galactose specificity-determining motif in the C-type lectins. In our previous study, replacement of the QPD motif by an EPN (Glu-Pro-Asn) motif led to a weak binding affinity for mannose. Therefore, we examined the effects of an additional mutation in the carbohydrate-binding site on the specificity of the lectin. METHODS: Trp105 of EPN-CEL-I was replaced by a histidine residue using site-directed mutagenesis, and the binding affinity of the resulting mutant, EPNH-CEL-I, was examined by sugar-polyamidoamine dendrimer assay, isothermal titration calorimetry, and glycoconjugate microarray analysis. Tertiary structure of the EPNH-CEL-I/mannose complex was determined by X-ray crystallographic analysis. RESULTS: Sugar-polyamidoamine dendrimer assay and glycoconjugate microarray analysis revealed a drastic change in the specificity of EPNH-CEL-I from galactose/N-acetylgalactosamine to mannose. The association constant of EPNH-CEL-I for mannose was determined to be 3.17x103M-1 at 25 degrees C. Mannose specificity of EPNH-CEL-I was achieved by stabilization of the binding of mannose in a correct orientation, in which the EPN motif can form proper hydrogen bonds with 3- and 4-hydroxy groups of the bound mannose. CONCLUSIONS: Specificity of CEL-I can be engineered by mutating a limited number of amino acid residues in addition to the QPD/EPN motifs. GENERAL SIGNIFICANCE: Versatility of the C-type carbohydrate-recognition domain structure in the recognition of various carbohydrate chains could become a promising platform to develop novel molecular recognition proteins.

Mannose-recognition mutant of the galactose/N-acetylgalactosamine-specific C-type lectin CEL-I engineered by site-directed mutagenesis.,Moriuchi H, Unno H, Goda S, Tateno H, Hirabayashi J, Hatakeyama T Biochim Biophys Acta. 2015 Apr 11;1850(7):1457-1465. doi:, 10.1016/j.bbagen.2015.04.004. PMID:25869490<ref>PMID:25869490</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 4wqq" style="background-color:#fffaf0;"></div>
== References ==
<references/>
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</StructureSection>
[[Category: Cucumaria echinata]]
[[Category: Large Structures]]
[[Category: Hatakeyama T]]
[[Category: Unno H]]