title: The crystal structure of a lectin from Butea monosperma: insight into its glycosylation and binding of ligands.
abstract: Crystal structure of a lectin purified from Butea monosperma seeds was determined by Molecular Replacement method. Its primary structure was determined by Tandem Mass Spectroscopy and electron density maps from X-ray diffraction data. Its quaternary structure was tetrameric, formed of two monomers, α and β, β appearing as truncated α. The occurrence of two tetramers in the asymmetric unit of the crystal might be a consequence of asymmetric contacts due to difference in glycosylation and variable loops structures, to form an 'octamer-structure'. The crystal structure showed binding pockets for γAbu, having a proposed role in plant defense, at the interface of canonical dimer-partners. Hemagglutination studies, enzyme kinetics, isothermal titration calorimetry and molecular dynamics showed that the lectin is specific to N-acetyl d-galactosamine, galactose and lactose in decreasing order, and α-amylase inhibitor.
authors.forename: J
authors.initials: J
authors.lastname: Abhilash
authors.forename: K
authors.initials: K
authors.lastname: Geethanandan
authors.forename: S R
authors.initials: SR
authors.lastname: Bharath
authors.forename: A
authors.initials: A
authors.lastname: Sabu
authors.forename: C
authors.initials: C
authors.lastname: Sadasivan
authors.forename: M
authors.initials: M
authors.lastname: Haridas
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites; D031290:Butea / Q000737:chemistry*; D002151:Calorimetry; D018360:Crystallography, X-Ray; D005990:Glycerol / Q000378:metabolism; D006031:Glycosylation; D007477:Ions; D007700:Kinetics; D008024:Ligands; D013058:Mass Spectrometry; D008670:Metals / Q000737:chemistry; D056004:Molecular Dynamics Simulation; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009844:Oligosaccharides / Q000737:chemistry; D037121:Plant Lectins / Q000737:chemistry* / Q000494:pharmacology; D011487:Protein Conformation; D012997:Solvents; D000516:alpha-Amylases / Q000037:antagonists & inhibitors / Q000378:metabolism; D005680:gamma-Aminobutyric Acid / Q000737:chemistry / Q000378:metabolism
chemical_list: D007477:Ions; D008024:Ligands; D008670:Metals; D009844:Oligosaccharides; D037121:Plant Lectins; D012997:Solvents; D005680:gamma-Aminobutyric Acid; D000516:alpha-Amylases; D005990:Glycerol