6ZU2 image
Entry Detail
PDB ID:
6ZU2
Title:
CML1 crystal structure in complex with H-type 1 trisaccharide
Biological Source:
Source Organism:
PDB Version:
Deposition Date:
2020-07-21
Release Date:
2021-07-28
Method Details:
Experimental Method:
Resolution:
1.55 Å
R-Value Free:
0.18
R-Value Work:
0.15
Space Group:
P 31
Macromolecular Entities
Polymer Type:polypeptide(L)
Description:Mucin-binding lectin 1
Chain IDs:A (auth: AAA), B (auth: BBB), C (auth: CCC), D (auth: DDD), E (auth: EEE), F (auth: FFF)
Chain Length:126
Number of Molecules:6
Biological Source:Coprinopsis cinerea
Ligand Molecules
Peptide-like Molecules
PRD_900049
Primary Citation
Structure-function relationship of a novel fucoside-binding fruiting body lectin from Coprinopsis cinerea exhibiting nematotoxic activity.
Glycobiology 32 600 615 (2022)
PMID: 35323921 DOI: 10.1093/glycob/cwac020

Abstact

Lectins are non-immunoglobulin-type proteins that bind to specific carbohydrate epitopes and play important roles in intra- and inter-organismic interactions. Here, we describe a novel fucose-specific lectin, termed CML1, which we identified from fruiting body extracts of Coprinopsis cinerea. For further characterization, the coding sequence for CML1 was cloned and heterologously expressed in Escherichia coli. Feeding of CML1-producing bacteria inhibited larval development of the bacterivorous nematode Caenorhabditis tropicalis, but not of C. elegans. The crystal structure of the recombinant protein in its apo-form and in complex with H type I or Lewis A blood group antigens was determined by X-ray crystallography. The protein folds as a sandwich of 2 antiparallel β-sheets and forms hexamers resulting from a trimer of dimers. The hexameric arrangement was confirmed by small-angle X-ray scattering (SAXS). One carbohydrate-binding site per protomer was found at the dimer interface with both protomers contributing to ligand binding, resulting in a hexavalent lectin. In terms of lectin activity of recombinant CML1, substitution of the carbohydrate-interacting residues His54, Asn55, Trp94, and Arg114 by Ala abolished carbohydrate-binding and nematotoxicity. Although no similarities to any characterized lectin were found, sequence alignments identified many non-characterized agaricomycete proteins. These results suggest that CML1 is the founding member of a novel family of fucoside-binding lectins involved in the defense of agaricomycete fruiting bodies against predation by fungivorous nematodes.

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Primary Citation of related structures