Conformational Changes in Small Ligands Upon Tetanus Toxin Binding

2008 ◽  
Author(s):  
Terry J. Henderson ◽  
Rossitza K. Gitti
Keyword(s):  
Conformational Changes ◽  
Tetanus Toxin ◽  
Toxin Binding ◽  
Small Ligands

scholarly journals Characterization of tetanus toxin binding to rat brain membranes. Evidence for a high-affinity proteinase-sensitive receptor

1986 ◽  
Vol 236 (3) ◽  
pp. 845-852 ◽  
Author(s):  
E J Pierce ◽  
M D Davison ◽  
R G Parton ◽  
W H Habig ◽  
D R Critchley
Keyword(s):  
Rat Brain ◽  
Tetanus Toxin ◽  
Binding Studies ◽  
Single Class ◽  
Toxin Binding ◽  
High Affinity ◽  
Brain Membranes ◽  
Protein Receptor ◽  
Rat Brain Membranes ◽  
Competition Binding

Binding of 125I-labelled tetanus toxin to rat brain membranes in 25 mM-Tris/acetate, pH 6.0, was saturable and there was a single class of high-affinity site (KD 0.26-1.14 nM) present in high abundance (Bmax. 0.9-1.89 nmol/mg). The sites were largely resistant to proteolysis and heating but were markedly sensitive to neuraminidase. Trisialogangliosides were effective inhibitors of toxin binding (IC50 10 nM) and trisialogangliosides inserted into membranes lacking a toxin receptor were able to bind toxin with high affinity (KD 2.6 nM). The results are consistent with previous studies and the hypothesis that di- and trisialogangliosides act as the primary receptor for tetanus toxin under these conditions. In contrast, when toxin binding was assayed in Krebs-Ringer buffer, pH 7.4, binding was greatly reduced, was non-saturable and competition binding studies showed evidence for a small number of high-affinity sites (KD 0.42 nM, Bmax. 0.90 pmol/mg) and a larger number of low-affinity sites (KD 146 nM, Bmax. 179 pmol/mg). Treatment of membranes with proteinases, heat, and neuraminidase markedly reduced binding. Trisialogangliosides were poor inhibitors of toxin binding (IC50 11.0 microM), and trisialogangliosides inserted into membranes bound toxin with low affinity. The results suggest that in physiological buffers tetanus toxin binds with high affinity to a protein receptor, and that gangliosides represent only a low-affinity site.

Tetanus toxin binding to isolated and cultured rat retinal glial cells

Glia ◽  
1988 ◽  
Vol 1 (2) ◽  
pp. 156-164 ◽  
Author(s):  
Reiner Huba ◽  
Hans-Dieter Hofmann
Keyword(s):  
Glial Cells ◽  
Tetanus Toxin ◽  
Toxin Binding

scholarly journals Batrachotoxin-modified sodium channels in planar lipid bilayers. Characterization of saxitoxin- and tetrodotoxin-induced channel closures.

1987 ◽  
Vol 89 (6) ◽  
pp. 873-903 ◽  
Author(s):  
W N Green ◽  
L B Weiss ◽  
O S Andersen
Keyword(s):  
Binding Site ◽  
Lipid Bilayers ◽  
Sodium Channels ◽  
Conformational Changes ◽  
Single Channel ◽  
Planar Lipid Bilayers ◽  
Net Charge ◽  
Toxin Binding ◽  
Wide Range ◽  
Voltage Dependent

The guanidinium toxin-induced inhibition of the current through voltage-dependent sodium channels was examined for batrachotoxin-modified channels incorporated into planar lipid bilayers that carry no net charge. To ascertain whether a net negative charge exists in the vicinity of the toxin-binding site, we studied the channel closures induced by tetrodotoxin (TTX) and saxitoxin (STX) over a wide range of [Na+]. These toxins carry charges of +1 and +2, respectively. The frequency and duration of the toxin-induced closures are voltage dependent. The voltage dependence was similar for STX and TTX, independent of [Na+], which indicates that the binding site is located superficially at the extracellular surface of the sodium channel. The toxin dissociation constant, KD, and the rate constant for the toxin-induced closures, kc, varied as a function of [Na+]. The Na+ dependence was larger for STX than for TTX. Similarly, the addition of tetraethylammonium (TEA+) or Zn++ increased KD and decreased kc more for STX than for TTX. These differential effects are interpreted to arise from changes in the electrostatic potential near the toxin-binding site. The charges giving rise to this potential must reside on the channel since the bilayers had no net charge. The Na+ dependence of the ratios KDSTX/KDTTX and kcSTX/kcTTX was used to estimate an apparent charge density near the toxin-binding site of about -0.33 e X nm-2. Zn++ causes a voltage-dependent block of the single-channel current, as if Zn++ bound at a site within the permeation path, thereby blocking Na+ movement. There was no measurable interaction between Zn++ at its blocking site and STX or TTX at their binding site, which suggests that the toxin-binding site is separate from the channel entrance. The separation between the toxin-binding site and the Zn++ blocking site was estimated to be at least 1.5 nm. A model for toxin-induced channel closures is proposed, based on conformational changes in the channel subsequent to toxin binding.

Neuronal acquisition of tetanus toxin binding sites: Relationship with the last mitotic cycle

1983 ◽  
Vol 100 (2) ◽  
pp. 350-357 ◽  
Author(s):  
Annette Koulakoff ◽  
Bernard Bizzini ◽  
Yoheved Berwald-Netter
Keyword(s):  
Binding Sites ◽  
Tetanus Toxin ◽  
Mitotic Cycle ◽  
Toxin Binding

A simplified method for the preparation of tetanus toxin binding fragment for neurobiology

1992 ◽  
Vol 42 (3) ◽  
pp. 229-236 ◽  
Author(s):  
Paul S. Fishman ◽  
Dawn A. Farrand ◽  
Jane L. Halpern ◽  
William C. Latham
Keyword(s):  
Tetanus Toxin ◽  
Toxin Binding ◽  
Simplified Method

Neural induction and in vitro initial expression of neurofilament and tetanus toxin binding site molecules in amphibians

1986 ◽  
Vol 18 (1) ◽  
pp. 57-64 ◽  
Author(s):  
A.M. Duprat ◽  
L. Gualandris ◽  
F. Foulquier ◽  
D. Paulin ◽  
B. Bizzini
Keyword(s):  
Binding Site ◽  
Tetanus Toxin ◽  
Neural Induction ◽  
Toxin Binding
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