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Publication Abstract from PubMed

D-Galactose-binding lectin from the octocoral, Sinularia lochmodes (SLL-2), distributes densely on the cell surface of microalgae, Symbiodinium sp., an endosymbiotic dinoflagellate of the coral, and is also shown to be a chemical cue that transforms dinoflagellate into a non-motile (coccoid) symbiotic state. SLL-2 binds with high affinity to the Forssman antigen (N-acetylgalactosamine(GalNAc)alpha1-3GalNAcbeta1-3Galalpha1-4Galbeta1-4Glc-ceram ide), and the presence of Forssman antigen-like sugar on the surface of Symbiodinium CS-156 cells was previously confirmed. Here we report the crystal structures of SLL-2 and its GalNAc complex as the first crystal structures of a lectin involved in the symbiosis between coral and dinoflagellate. N-Linked sugar chains and a galactose derivative binding site common to H-type lectins were observed in each monomer of the hexameric SLL-2 crystal structure. In addition, unique sugar-binding site-like regions were identified at the top and bottom of the hexameric SLL-2 structure. These structural features suggest a possible binding mode between SLL-2 and Forssman antigen-like pentasaccharide.

Crystal structure of a symbiosis-related lectin from octocoral.,Kita A, Jimbo M, Sakai R, Morimoto Y, Miki K Glycobiology. 2015 Sep;25(9):1016-23. doi: 10.1093/glycob/cwv033. Epub 2015 May, 28. PMID:26022515^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.