bi5005014_si_001.pdf (151.88 kB)
Structural Characterization of the DC-SIGN–LewisX Complex
journal contribution
posted on 2015-12-17, 04:08 authored by Kari Pederson, Daniel
A. Mitchell, James H. PrestegardDendritic
cell-specific intracellular adhesion molecule-3-grabbing
nonintegrin (DC-SIGN) is a C-type lectin highly expressed on the surface
of antigen-presenting dendritic cells. DC-SIGN mediates interactions
among dendritic cells, pathogens, and a variety of epithelia, myeloid
cells, and endothelia by binding to high mannose residues on pathogenic
invaders or fucosylated residues on the membranes of other immune
cells. Although these interactions are normally beneficial, they can
also contribute to disease. The structural characterization of binding
geometries is therefore of interest as a basis for the construction
of mimetics that can mediate the effects of abnormal immune response.
Here, we report the structural characteristics of the interaction
of the DC-SIGN carbohydrate recognition domain (CRD) with a common
fucosylated entity, the LewisX trisaccharide (LeX), using NMR methods. Titration of the monomeric DC-SIGN CRD with
LeX monitored by 2D NMR revealed significant perturbations
of DC-SIGN cross-peak positions in 1H–15N heteronuclear single quantum coherence (HSQC) spectra and identified
residues near the binding site. Additionally, saturation transfer
difference (STD) and transferred nuclear Overhauser effect (trNOE)
NMR experiments, using a tetrameric form of DC-SIGN, identified binding
epitopes and bound conformations of the LeX ligand. The
restraints derived from these multiple experiments were used to generate
models for the binding of LeX to the DC-SIGN CRD. Ranking
of the models based on the fit of model-based simulations of the trNOE
data and STD buildup curves suggested conformations distinct from
those seen in previous crystal structures. The new conformations offer
insight into how differences between binding of LewisX and
mannose-terminated saccharides may be propagated.
History
Usage metrics
Categories
Keywords
binding epitopesSTD buildup curvesbinding geometriesNMR experimentsmannose residuesLeX ligandCRDHSQCconformations offer insightinteractionquantum coherencefucosylated residuesOverhauser effect2 D NMRLewisX trisaccharidetrNOE datasaturation transfer differencetetrameric formbinding sitefucosylated entitymyeloid cellscrystal structuresStructural CharacterizationNMR methodsdendritic cells
Licence
Exports
RefWorks
BibTeX
Ref. manager
Endnote
DataCite
NLM
DC