2Z49

Crystal Structure of Hemolytic Lectin CEL-III Complexed with methyl-alpha-D-galactopylanoside

Summary for 2Z49

• Entry DOI: 10.2210/pdb2z49/pdb
• Related: 1VCL 2Z48
• Descriptor: Hemolytic lectin CEL-III, methyl alpha-D-galactopyranoside, CALCIUM ION, ... (5 entities in total)
• Functional Keywords: lectin, cel-iii, hemolysis, hemagglutination, pore-forming, calcium, magnesium, methyl-alpha-d-galactopylanoside, toxin
• Biological source: Cucumaria echinata
• Total number of polymer chains: 2
• Total formula weight: 97344.15

Authors

Hatakeyama, T.,Unno, H.,Eto, S.,Hidemura, H.,Uchida, T.,Kouzuma, Y. (deposition date: 2007-06-13, release date: 2007-10-30, Last modification date: 2024-10-23)

Primary citation

Hatakeyama, T.,Unno, H.,Kouzuma, Y.,Uchida, T.,Eto, S.,Hidemura, H.,Kato, N.,Yonekura, M.,Kusunoki, M.
C-type lectin-like carbohydrate-recognition of the hemolytic lectin CEL-III containing ricin-type beta-trefoil folds
J.Biol.Chem., 282:37826-37835, 2007

PubMed Abstract: CEL-III is a Ca(2+)-dependent hemolytic lectin, isolated from the marine invertebrate Cucumaria echinata. The three-dimensional structure of CEL-III/GalNAc and CEL-III/methyl alpha-galactoside complexes was solved by x-ray crystallographic analysis. In these complexes, five carbohydrate molecules were found to be bound to two carbohydrate-binding domains (domains 1 and 2) located in the N-terminal 2/3 portion of the polypeptide and that contained beta-trefoil folds similar to ricin B-chain. The 3-OH and 4-OH of bound carbohydrate molecules were coordinated with Ca(2+) located at the subdomains 1alpha, 1gamma, 2alpha, 2beta, and 2gamma, simultaneously forming hydrogen bond networks with nearby amino acid side chains, which is similar to carbohydrate binding in C-type lectins. The binding of carbohydrates was further stabilized by aromatic amino acid residues, such as tyrosine and tryptophan, through a stacking interaction with the hydrophobic face of carbohydrates. The importance of amino acid residues in the carbohydrate-binding sites was confirmed by the mutational analyses. The orientation of bound GalNAc and methyl alpha-galactoside was similar to the galactose moiety of lactose bound to the carbohydrate-binding site of the ricin B-chain, although the ricin B-chain does not require Ca(2+) ions for carbohydrate binding. The binding of the carbohydrates induced local structural changes in carbohydrate-binding sites in subdomains 2alpha and 2beta. Binding of GalNAc also induced a slight change in the main chain structure of domain 3, which could be related to the conformational change upon binding of specific carbohydrates to induce oligomerization of the protein.

PubMed: 17977832
DOI: 10.1074/jbc.M705604200

Experimental method

X-RAY DIFFRACTION (1.95 Å)