title: Conformational change of a unique sequence in a fungal galectin from Agrocybe cylindracea controls glycan ligand-binding specificity.
abstract: A fungal galectin from Agrocybe cylindracea (ACG) exhibits broad binding specificity for β-galactose-containing glycans. We determined the crystal structures of wild-type ACG and the N46A mutant, with and without glycan ligands. From these structures and a saccharide-binding analysis of the N46A mutant, we revealed that a conformational change of a unique insertion sequence containing Asn46 provides two binding modes for ACG, and thereby confers broad binding specificity. We propose that the unique sequence provides these two distinct glycan-binding modes by an induced-fit mechanism.
authors.affiliation: Structural Biology Research Center, Photon Factory, Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba, Ibaraki 305-0801, Japan.
authors.forename: Naoyuki
authors.initials: N
authors.lastname: Kuwabara
authors.forename: Dan
authors.initials: D
authors.lastname: Hu
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Tateno
authors.forename: Hisayoshi
authors.initials: H
authors.lastname: Makyio
authors.forename: Jun
authors.initials: J
authors.lastname: Hirabayashi
authors.forename: Ryuichi
authors.initials: R
authors.lastname: Kato
mesh_terms: D055362:Agrocybe; D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D018360:Crystallography, X-Ray; D005656:Fungal Proteins / Q000737:chemistry* / Q000235:genetics; D037161:Galectins / Q000737:chemistry* / Q000235:genetics; D006860:Hydrogen Bonding; D007785:Lactose; D008024:Ligands; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011485:Protein Binding; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary
chemical_list: D005656:Fungal Proteins; D037161:Galectins; D008024:Ligands; D007785:Lactose
keywords: A-tetra; ACG; Agrocybe cylindracea galectin; CRD; GalNAcα1–3(Fucα1-2)Galβ1–4GlcNAc; Galectin; Glycan; PEG; Protein engineering; RMSD; Saccharide; X-ray crystallography; carbohydrate recognition domain; polyethylene glycol; root-mean-square deviation