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Neutron crystal structure of perdeuterated galectin-3C in complex with lactoseNeutron crystal structure of perdeuterated galectin-3C in complex with lactose
Structural highlights
Function[LEG3_HUMAN] Galactose-specific lectin which binds IgE. May mediate with the alpha-3, beta-1 integrin the stimulation by CSPG4 of endothelial cells migration. Together with DMBT1, required for terminal differentiation of columnar epithelial cells during early embryogenesis (By similarity). In the nucleus: acts as a pre-mRNA splicing factor. Involved in acute inflammatory responses including neutrophil activation and adhesion, chemoattraction of monocytes macrophages, opsonization of apoptotic neutrophils, and activation of mast cells.[1] [2] [3] Publication Abstract from PubMedThe medically important drug target galectin-3 binds galactose-containing moieties on glycoproteins through an intricate pattern of hydrogen bonds to a largely polar surface-exposed binding site. All successful inhibitors of galectin-3 to date have been based on mono- or disaccharide cores closely resembling natural ligands. A detailed understanding of the H-bonding networks in these natural ligands will provide an improved foundation for the design of novel inhibitors. Neutron crystallography is an ideal technique to reveal the geometry of hydrogen bonds, because the positions of hydrogen atoms are directly detected rather than being inferred from the positions of heavier atoms as in X-ray crystallography. We present three neutron crystal structures of the C-terminal carbohydrate recognition domain of galectin-3: the ligand-free form, the complex with the natural substrate lactose, and with glycerol, which mimics important interactions made by lactose. The neutron crystal structures reveal unambiguously the exquisite fine-tuning of the hydrogen bonding pattern in the binding site to the natural disaccharide ligand. The ligand-free structure shows that most of these hydrogen bonds are preserved even when the polar groups of the ligand are replaced by water molecules. The protonation states of all histidine residues in the protein are also revealed and correlate well with NMR observations. The structures give a solid starting point for molecular dynamics simulations and computational estimates of ligand binding affinity that will inform future drug design. Elucidation of hydrogen bonding patterns in ligand-free, lactose- and glycerol-bound galectin-3C by neutron crystallography to guide drug design.,Manzoni F, Wallerstein J, Schrader TE, Ostermann A, Coates L, Akke M, Blakeley MP, Oksanen E, Logan DT J Med Chem. 2018 Apr 19. doi: 10.1021/acs.jmedchem.8b00081. PMID:29672051[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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