4ym0

</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=BGC:BETA-D-GLUCOSE'>BGC</scene>, <scene name='pdbligand=GAL:BETA-D-GALACTOSE'>GAL</scene>, <scene name='pdbligand=GOL:GLYCEROL'>GOL</scene>, <scene name='pdbligand=NAG:N-ACETYL-D-GLUCOSAMINE'>NAG</scene>, <scene name='pdbligand=PRD_900004:beta-lactose'>PRD_900004</scene></td></tr>

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== Publication Abstract from PubMed ==

Human galectin-4 is a lectin that is expressed mainly in the gastrointestinal tract and exhibits metastasis-promoting roles in some cancers. Its tandem-repeat nature exhibits two distinct carbohydrate recognition domains allowing cross-linking by simultaneous binding to sulfated and non-sulfated (but not sialylated) glycosphingolipids and glycoproteins; facilitating stabilisation of lipid rafts. Critically, galectin-4 exerts favourable or unfavourable effects depending upon the cancer. Here we report the first X-ray crystallographic structural information on human galectin-4, specifically the C-terminal carbohydrate recognition domain of human (galectin-4C) in complex with lactose, lactose-3'-sulfate, 2'-fucosyllactose, lacto-N-tetraose and lacto-N-neotetraose. These structures enable elucidation of galectin-4C binding fine-specificity towards sulfated and non-sulfated lacto- and neolacto-series sphingolipids as well as to human blood group antigens. Analysis of the lactose-3'-sulfate complex structure shows that galectin-4C does not recognise the sulfate group using any specific amino acid, but binds the ligand nonetheless. Complex structures with lacto-N-tetraose and lacto-N-neotetraose displayed differences in binding interactions exhibited by the non-reducing-end galactose. That of lacto-N-tetraose points outward from the protein surface whereas that of lacto-N-neotetraose interacts directly with the protein. Recognition patterns of human galectin-4C towards lacto- and neolacto-series glycosphingolipids are similar to those of human galectin-3, however detailed scrutiny revealed differences stemming from the extended binding-site that offer distinction in ligand profiles of these two galectins. Structural characterisation of the complex with 2'-fucosyllactose, a carbohydrate with similarity to the H-antigen, and molecular dynamics studies highlight structural features that allow specific recognition of A- and B-antigens, whilst a lack of interaction with the 2'-fucose of blood group antigens was revealed. This article is protected by copyright. All rights reserved.

Structural characterisation of human galectin-4 C-terminal domain -elucidating the molecular basis for recognition of glycosphingolipids, sulfated saccharides and blood group antigens.,Bum-Erdene K, Leffler H, Nilsson UJ, Blanchard H FEBS J. 2015 Jun 16. doi: 10.1111/febs.13348. PMID:26077389<ref>PMID:26077389</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>

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== References ==

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