Mirtha J Biscoglio de Jiménez Bonino

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Peptides corresponding to the sequence alpha 124-147 of the Torpedo californica and Homo sapiens nicotinic cholinergic receptors were synthesized. The His residue at position 134 was ethoxyformylated or substituted by Ala. Effects of such modifications were studied by: (a) a toxin blot assay and (b) a competition assay between each peptide and the Discopyge(More)
Stings by insects from the Hymenoptera order are known to cause life-threatening allergic reactions and impair life quality. Despite the effectiveness of conventional vespid venom immunotherapy, more standardized and safer allergy vaccines are required and recombinant hypoallergenic variants are important clinical tools. Antigen 5 is a major allergen of(More)
The muscle-type nicotinic receptor has two pharmacologically distinguishable acetylcholine binding sites at the alpha-gamma and alpha-delta subunit interfaces; alpha-conotoxins can bind them selectively. As reported, alpha-conotoxin MI has greater affinity for the site near the alpha-delta interface of the BC(3)H1 cell receptor but, in the case of the(More)
Reactivity of histidine residues of the Discopyge tschudii nicotinic acetylcholine receptor was studied by reaction with DEP and the influence of their modification on functional properties of the receptor was evaluated. Determination of two kinetically distinguishable classes was achieved. The fast-reacting class is composed of 7 histidine residues with an(More)
Histidine residues have been shown to be critical for alpha-BgTx binding to the acetylcholine receptor (Lacorazza et al., 1992; Bouzat et al., 1993; Lacorazza et al., 1995). Receptor subunits from Discopyge tschudii were modified with diethylpyrocarbonate (DEP). DEP treatment produces a concentration-dependent decrease of [125I] alpha-BgTx binding to the(More)
We have examined the effect of chemical modification with diethyl pyrocarbonate (DEP) on the properties of acetylcholine (ACh)-activated channels in the cloned muscle-cell line BC3H-1. After protein modification, patch-clamp recordings showed alterations in the kinetics of the nicotinic acetylcholine receptor (AChR) channel. The major effect was observed in(More)
The effects of chemical modification of a disulfide bond(s) (-SS-) or sulfhydryl group(s) (-SH) on the [3H]-flunitrazepam ([3H]FNZ) binding to membrane-bound or immunoprecipitated benzodiazepine (BZD) receptors (BZD-R) from bovine cerebral cortex were examined. Reduction of -SS- with dithiothreitol (DTT) brought about a reversible, time- and dose-dependent(More)
This paper studies the effect of histidine chemical modification of the membrane-bound acetylcholine receptor from Discopyge tschudii on its specific alpha-bungarotoxin binding. The acylating reagent ethoxyformic anhydride (diethyl pyrocarbonate, DEP), was used. DEP-treatment induces a loss of binding capacity, time and DEP-concentration dependent. After a(More)
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