摘要：SummarySiglecs (sialic acid binding immunoglobulin (Ig)-like lectins) constitute a group of 15 human and 9 murine cell-surface transmembrane receptors belonging to the I-type lectin family, mostly expressed on innate immune cells and characterized by broadly similar structural features. Here, the prominent inhibitory CD22 (Siglec-2), well known in maintaining tolerance and preventing autoimmune responses on B cells, is studied in its human and murine forms in complex with sialoglycans. In detail, the role of theN-glycolyl neuraminic acid (Neu5Gc) moiety in the interaction with both orthologues was explored. The analysis of the binding mode was carried out by the combination of NMR spectroscopy, computational approaches, and CORCEMA-ST calculations. Our findings provide a first model of Neu5Gc recognition by h-CD22 and show a comparable molecular recognition profile by h- and m-CD22. These data open the way to innovative diagnostic and/or therapeutic methodologies to be used in the modulation of the immune responses.Graphical abstractDisplay OmittedHighlights•The structural basis of sialoglycans recognition by h/m CD22 has been investigated•The binding modes of Neu5Gc-/Neu5Ac-containing ligands to m/h-CD22 were compared•The bioactive conformation of sialoglycans has been derived•Our findings may help in the regulation of immune response and cancer preventionBiochemistry; Immunology; Structural Biology
