5T20

Crystal Structure of Tarin Lectin bound to Trimannose

Summary for 5T20

• Entry DOI: 10.2210/pdb5t20/pdb
• Related: 5T1X
• Related PRD ID: PRD_900118
• Descriptor: Lectin, alpha-D-mannopyranose-(1-3)-[alpha-D-mannopyranose-(1-6)]alpha-D-mannopyranose, alpha-D-mannopyranose-(1-6)-alpha-D-mannopyranose, ... (7 entities in total)
• Functional Keywords: tarin, gna-related lectin, sugar binding protein
• Biological source: Colocasia esculenta (Wild taro); More
• Total number of polymer chains: 16
• Total formula weight: 203118.77

Authors

Pereira, P.R.,Meagher, J.L.,Stuckey, J.A. (deposition date: 2016-08-22, release date: 2016-09-14, Last modification date: 2023-10-04)

Primary citation

Pereira, P.R.,Meagher, J.L.,Winter, H.C.,Goldstein, I.J.,Paschoalin, V.M.,Silva, J.T.,Stuckey, J.A.
High-resolution crystal structures of Colocasia esculenta tarin lectin.
Glycobiology, 27:50-56, 2017

PubMed 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 (QxDxNxVxYxWX) 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.

PubMed: 27558840
DOI: 10.1093/glycob/cww083

Experimental method

X-RAY DIFFRACTION (1.91 Å)