Scorpion neurotoxin Ts-gamma was isolated from Tityus serrulatus venom and purified to apparent homogeneity by ion-exchange HPLC. Crystals of the toxin were grown using polyethylene glycol 6000 as precipitant and were found to belong to the monoclinic space group P21 with cell parameters a = 22.20, b = 36.90, c = 31.57 A, beta = 100.85 degrees. The crystals diffract beyond 1.73 A resolution at a synchrotron beamline, being notably stable during X-ray exposure. The structure has been solved by molecular replacement using the very high resolution structure of Sahara scorpion Androctonus australis Hector (PDB code 1AHO) as a search model.
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http://dx.doi.org/10.1107/s0907444998007197 | DOI Listing |
Cell Mol Neurobiol
December 2004
Departamento de Farmacologia, Instituto de Ciências Biológicas, UFMG, 31270-901-Belo Horizonte, MG-Brasil.
1. We have investigated the effect of tityus gamma (TiTX gamma) scorpion toxin on the release of [3H]dopamine in rat brain prefrontal cortical slices. The stimulatory effect of TiTX gamma on the release of [3H]dopamine was dose/time-dependent with an EC50 of 0.
View Article and Find Full Text PDFCell Calcium
January 2004
Department of Biostatistics and Computing, Brain Image Analysis Unit, Institute of Psychiatry, King's College, De Crespigny Park, Denmark Hill, P.O. Box 22, London SE5 8AF, UK.
Using confocal microscopy, we have examined the increases in [Ca(2+)](i) evoked by sodium channel toxins in cells labelled with the fluorescent dye INDO-1. We describe a new image analysis method that improves the detection of region-specific, toxin-induced patterns of change of intracellular calcium. This method is based on correction of global image motion followed by calculation of the strength of correlation between calcium changes in "seed" or reference pixels chosen to represent different regions of cells and those in other regions of the image.
View Article and Find Full Text PDFToxicon
June 2003
Departamento de Fisiologia e Biofísica, Instituto de Biologia, Universidade Estadual de Campinas (UNICAMP), CP 6109, CEP 13083-970 Campinas SP, Brazil.
The effects of TsTx-V, an alpha-toxin isolated from Tityus serrulatus venom, on electrical activity and insulin secretion by rodent pancreatic islet cells were studied. TsTx-V (5.6 microg/ml) depolarized mouse pancreatic beta-cells, diminished the membrane input resistance and increased the duration of the active phase of glucose-induced electrical activity.
View Article and Find Full Text PDFCell Mol Neurobiol
December 2002
Laboratório de Neurofarmacologia, Departamento de Farmacologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil.
1. Voltage-gated Na+ channels are responsible for initiation and conduction of action potentials. The arrival of an action potential at nerve terminal increases intracellular Na+ and Ca2+ concentrations.
View Article and Find Full Text PDFNeuroreport
September 2001
Laboratório de Neurofarmacologia, Departamento de Farmacologia, Faculdade de Medicina, ICB-UFMG, Av. Antonio Carlos 6627-Pampulha, 31270-901-Belo Horizonte MG, Brazil.
The effect of the beta-scorpion toxin, TiTX gamma on the release of [3H]GABA from rat brain cortical slices is described. The stimulatory effect of TiTX gamma on the release of [3H]GABA was dependent on incubation time and TiTX gamma concentration with an EC50 of 0.19 microM.
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