5xrg | pdb_00005xrg
Galectin-10/Charcot-Leyden crystal protein crystal structure
Structural highlights
Function[LEG10_HUMAN] Regulates immune responses through the recognition of cell-surface glycans. Essential for the anergy and suppressive function of CD25-positive regulatory T-cells (Treg).[1] Publication Abstract from PubMedGalectin-10 (Gal-10) which forms Charcot-Leyden crystals in vivo, is crucial to regulating lymph cell function. Here, we solved the crystal structures of Gal-10 and eight variants at resolutions of 1.55-2.00 A. Structural analysis and size exclusion chromatography demonstrated that Gal-10 dimerizes with a novel global shape that is different from that of other prototype galectins (e.g., Gal-1, -2 and -7). In the Gal-10 dimer, Glu33 from one subunit modifies the carbohydrate binding site of another, essentially inhibiting disaccharide binding. Nevertheless, glycerol (and possibly other small hydroxylated molecules) can interact with residues at the ligand binding site, with His53 being the most crucial for binding. Alanine substitution of the conserved Trp residue (Trp72) that is crucial to saccharide binding in other galectins, actually leads to enhanced erythrocyte agglutination, suggesting that Trp72 negatively regulates Gal-10 ligand binding. Overall, our crystallographic and biochemical results provide insight into Gal-10 ligand binding specificity. Galectin-10: a new structural type of prototype galectin dimer and effects on saccharide ligand binding.,Su J, Gao J, Si Y, Cui L, Song C, Wang Y, Wu R, Tai G, Zhou Y Glycobiology. 2017 Dec 23. pii: 4773962. doi: 10.1093/glycob/cwx107. PMID:29293962[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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