title: High-resolution crystal structures of Colocasia esculenta tarin lectin.
abstract: Tarin, the Colocasia esculenta lectin from the superfamily of α-d-mannose-specific plant bulb lectins, is a tetramer of 47 kDa composed of two heterodimers. Each heterodimer possesses homologous monomers of ~11.9 (A chain) and ~12.7 (B chain) kDa. The structures of apo and carbohydrate-bound tarin were solved to 1.7 Å and 1.91 Å, respectively. Each tarin monomer forms a canonical β-prism II fold, common to all members of Galanthus nivalis agglutinin (GNA) family, which is partially stabilized by a disulfide bond and a conserved hydrophobic core. The heterodimer is formed through domain swapping involving the C-terminal β-strand and the β-sheet on face I of the prism. The tetramer is assembled through the dimerization of the B chains from heterodimers involving face II of each prism. The 1.91 Å crystal structure of tarin bound to Manα(1,3)Manα(1,6)Man reveals an expanded carbohydrate-binding sequence (QxDxNxVxYx4/6WX) on face III of the β-prism. Both monomers possess a similar fold, except for the length of the loop, which begins after the conserved tyrosine and creates the binding pocket for the α(1,6)-terminal mannose. This loop differs in size and amino-acid composition from 10 other β-prism II domain proteins, and may confer carbohydrate-binding specificity among members of the GNA-related lectin family.
authors: Centro de Tecnologia, Universidade Federal do Rio de Janeiro (UFRJ), Avenida Athos da Silveira Ramos, 149., Rio de Janeiro 21941-909, Brazil.|Department of Biological Chemistry, University of Michigan, 1150 W. Medical Center Drive, Ann Arbor, MI 48109, USA.
authors: Patricia R
authors: PR
authors: Pereira
authors: Center for Structural Biology, Life Sciences Institute, University of Michigan, 210 Washtenaw Ave, Ann Arbor, MI 48109, USA.
authors: Jennifer L
authors: JL
authors: Meagher
authors: Department of Biological Chemistry, University of Michigan, 1150 W. Medical Center Drive, Ann Arbor, MI 48109, USA.
authors: Harry C
authors: HC
authors: Winter
authors: Department of Biological Chemistry, University of Michigan, 1150 W. Medical Center Drive, Ann Arbor, MI 48109, USA.
authors: Irwin J
authors: IJ
authors: Goldstein
authors: Centro de Tecnologia, Universidade Federal do Rio de Janeiro (UFRJ), Avenida Athos da Silveira Ramos, 149., Rio de Janeiro 21941-909, Brazil.
authors: Vânia M F
authors: VM
authors: Paschoalin
authors: Centro de Tecnologia, Universidade Federal do Rio de Janeiro (UFRJ), Avenida Athos da Silveira Ramos, 149., Rio de Janeiro 21941-909, Brazil.
authors: Joab T
authors: JT
authors: Silva
authors: Department of Biological Chemistry, University of Michigan, 1150 W. Medical Center Drive, Ann Arbor, MI 48109, USA jass@umich.edu.|Center for Structural Biology, Life Sciences Institute, University of Michigan, 210 Washtenaw Ave, Ann Arbor, MI 48109, USA.
authors: Jeanne A
authors: JA
authors: Stuckey
mesh_terms: D000595:Amino Acid Sequence / Q000235:genetics; D001665:Binding Sites; D031060:Colocasia / Q000737:chemistry*; D018360:Crystallography, X-Ray; D005916:Globulins / Q000737:chemistry* / Q000235:genetics; D037241:Mannose-Binding Lectins / Q000737:chemistry* / Q000235:genetics; D008958:Models, Molecular; D010940:Plant Proteins / Q000737:chemistry* / Q000235:genetics; D011487:Protein Conformation; D017386:Sequence Homology, Amino Acid
chemical_list: D005916:Globulins; D037241:Mannose-Binding Lectins; D010940:Plant Proteins; C094238:TAR1 protein, Colocasia esculenta
keywords: Colocasia esculenta; Manα(1,3)Manα(1,6)Man; lectinn; tarin; β-prism