5MXC image
Entry Detail
PDB ID:
5MXC
Title:
Aleuria aurantia lectin (AAL) N224Q mutant in complex with alpha-methyl-L-fucoside
Biological Source:
Source Organism:
PDB Version:
Deposition Date:
2017-01-22
Release Date:
2017-12-20
Method Details:
Experimental Method:
Resolution:
1.14 Å
R-Value Free:
0.14
R-Value Work:
0.13
R-Value Observed:
0.13
Space Group:
C 1 2 1
Macromolecular Entities
Polymer Type:polypeptide(L)
Description:Fucose-specific lectin
Chain IDs:A
Chain Length:325
Number of Molecules:1
Biological Source:Aleuria aurantia
Primary Citation
Influence of Trp flipping on carbohydrate binding in lectins. An example on Aleuria aurantia lectin AAL.
PLoS ONE 12 e0189375 e0189375 (2017)
PMID: 29232414 DOI: 10.1371/journal.pone.0189375

Abstact

Protein-carbohydrate interactions are very often mediated by the stacking CH-π interactions involving the side chains of aromatic amino acids such as tryptophan (Trp), tyrosine (Tyr) or phenylalanine (Phe). Especially suitable for stacking is the Trp residue. Analysis of the PDB database shows Trp stacking for 265 carbohydrate or carbohydrate like ligands in 5 208 Trp containing motives. An appropriate model system to study such an interaction is the AAL lectin family where the stacking interactions play a crucial role and are thought to be a driving force for carbohydrate binding. In this study we present data showing a novel finding in the stacking interaction of the AAL Trp side chain with the carbohydrate. High resolution X-ray structure of the AAL lectin from Aleuria aurantia with α-methyl-l-fucoside ligand shows two possible Trp side chain conformations with the same occupation in electron density. The in silico data shows that the conformation of the Trp side chain does not influence the interaction energy despite the fact that each conformation creates interactions with different carbohydrate CH groups. Moreover, the PDB data search shows that the conformations are almost equally distributed across all Trp-carbohydrate complexes, which would suggest no substantial preference for one conformation over another.

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