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Glycans Confer Specificity to the Recognition of Ganglioside Receptors by Botulinum Neurotoxin A

Hamark, Christoffer ; Berntsson, Ronnie P-A ; Masuyer, Geoffrey ; Henriksson, Linda M ; Gustafsson, Robert ; Stenmark, Pål LU orcid and Widmalm, Göran (2017) In Journal of the American Chemical Society 139(1). p.218-230
Abstract

The highly poisonous botulinum neurotoxins, produced by the bacterium Clostridium botulinum, act on their hosts by a high-affinity association to two receptors on neuronal cell surfaces as the first step of invasion. The glycan motifs of gangliosides serve as initial coreceptors for these protein complexes, whereby a membrane protein receptor is bound. Herein we set out to characterize the carbohydrate minimal binding epitope of the botulinum neurotoxin serotype A. By means of ligand-based NMR spectroscopy, X-ray crystallography, computer simulations, and isothermal titration calorimetry, a screening of ganglioside analogues together with a detailed characterization of various carbohydrate ligand complexes with the toxin were... (More)

The highly poisonous botulinum neurotoxins, produced by the bacterium Clostridium botulinum, act on their hosts by a high-affinity association to two receptors on neuronal cell surfaces as the first step of invasion. The glycan motifs of gangliosides serve as initial coreceptors for these protein complexes, whereby a membrane protein receptor is bound. Herein we set out to characterize the carbohydrate minimal binding epitope of the botulinum neurotoxin serotype A. By means of ligand-based NMR spectroscopy, X-ray crystallography, computer simulations, and isothermal titration calorimetry, a screening of ganglioside analogues together with a detailed characterization of various carbohydrate ligand complexes with the toxin were accomplished. We show that the representation of the glycan epitope to the protein affects the details of binding. Notably, both branches of the oligosaccharide GD1a can associate to botulinum neurotoxin serotype A when expressed as individual trisaccharides. It is, however, the terminal branch of GD1a as well as this trisaccharide motif alone, corresponding to the sialyl-Thomsen-Friedenreich antigen, that represents the active ligand epitope, and these compounds bind to the neurotoxin with a high degree of predisposition but with low affinities. This finding does not correlate with the oligosaccharide moieties having a strong contribution to the total affinity, which was expected to be the case. We here propose that the glycan part of the ganglioside receptors mainly provides abundance and specificity, whereas the interaction with the membrane itself and protein receptor brings about the strong total binding of the toxin to the neuronal membrane.

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author
; ; ; ; ; and
publishing date
type
Contribution to journal
publication status
published
keywords
Botulinum Toxins, Type A/chemistry, Carbohydrate Conformation, Crystallography, X-Ray, Ligands, Models, Molecular, Nuclear Magnetic Resonance, Biomolecular, Polysaccharides/chemistry, Receptors, Cell Surface/chemistry
in
Journal of the American Chemical Society
volume
139
issue
1
pages
218 - 230
publisher
The American Chemical Society (ACS)
external identifiers
  • pmid:27958736
  • scopus:85019757417
ISSN
1520-5126
DOI
10.1021/jacs.6b09534
language
English
LU publication?
no
id
6d1968b8-6374-473a-882e-5b8832c7705b
date added to LUP
2019-05-07 08:13:46
date last changed
2024-04-02 01:27:43
@article{6d1968b8-6374-473a-882e-5b8832c7705b,
  abstract     = {{<p>The highly poisonous botulinum neurotoxins, produced by the bacterium Clostridium botulinum, act on their hosts by a high-affinity association to two receptors on neuronal cell surfaces as the first step of invasion. The glycan motifs of gangliosides serve as initial coreceptors for these protein complexes, whereby a membrane protein receptor is bound. Herein we set out to characterize the carbohydrate minimal binding epitope of the botulinum neurotoxin serotype A. By means of ligand-based NMR spectroscopy, X-ray crystallography, computer simulations, and isothermal titration calorimetry, a screening of ganglioside analogues together with a detailed characterization of various carbohydrate ligand complexes with the toxin were accomplished. We show that the representation of the glycan epitope to the protein affects the details of binding. Notably, both branches of the oligosaccharide GD1a can associate to botulinum neurotoxin serotype A when expressed as individual trisaccharides. It is, however, the terminal branch of GD1a as well as this trisaccharide motif alone, corresponding to the sialyl-Thomsen-Friedenreich antigen, that represents the active ligand epitope, and these compounds bind to the neurotoxin with a high degree of predisposition but with low affinities. This finding does not correlate with the oligosaccharide moieties having a strong contribution to the total affinity, which was expected to be the case. We here propose that the glycan part of the ganglioside receptors mainly provides abundance and specificity, whereas the interaction with the membrane itself and protein receptor brings about the strong total binding of the toxin to the neuronal membrane.</p>}},
  author       = {{Hamark, Christoffer and Berntsson, Ronnie P-A and Masuyer, Geoffrey and Henriksson, Linda M and Gustafsson, Robert and Stenmark, Pål and Widmalm, Göran}},
  issn         = {{1520-5126}},
  keywords     = {{Botulinum Toxins, Type A/chemistry; Carbohydrate Conformation; Crystallography, X-Ray; Ligands; Models, Molecular; Nuclear Magnetic Resonance, Biomolecular; Polysaccharides/chemistry; Receptors, Cell Surface/chemistry}},
  language     = {{eng}},
  month        = {{01}},
  number       = {{1}},
  pages        = {{218--230}},
  publisher    = {{The American Chemical Society (ACS)}},
  series       = {{Journal of the American Chemical Society}},
  title        = {{Glycans Confer Specificity to the Recognition of Ganglioside Receptors by Botulinum Neurotoxin A}},
  url          = {{http://dx.doi.org/10.1021/jacs.6b09534}},
  doi          = {{10.1021/jacs.6b09534}},
  volume       = {{139}},
  year         = {{2017}},
}