A conformational epitope in the N-terminus of the Escherichia coli heat-stable enterotoxins is involved in receptor-ligand interactions

Garrett, Beatrice Maria and Visweswariah, Sandhya S (1996) A conformational epitope in the N-terminus of the Escherichia coli heat-stable enterotoxins is involved in receptor-ligand interactions. In: Biochimica et Biophysica Acta, 1317 (02). pp. 149-154.

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Abstract

The heat-stable enterotoxins are a family of low molecular weight, cysteine rich peptide toxins which are one of the major causes of watery diarrhea in children and adults. These toxins bind to a cell surface receptor in intestinal cells and mediate their action through elevation of intracellular cyclic GMP. We have generated a monoclonal antibody to these peptide toxins which is able to neutralise the activity of the peptides in a human colonic cell line, the T84 cell line. The monoclonal antibody, ST:G8, appears to be directed to an epitope distinct from antibodies previously generated, and prior incubation of this antibody, or Fab generated from this antibody, with full length STh and STp peptides prevents cGMP accumulation in T84 cells. This inhibition is a direct result of the antibody preventing binding of the peptides to the receptor. ST:G8 Mab does not recognize a 13-mer biologically active analog of STp, comprising the core sequence of STp peptide, suggesting that it is directed to a region in the N-terminus of the peptides, which may modulate receptor interaction/activation. The antibody recognizes a conformational epitope in the ST peptides, since reduction and carboxyamidation of ST abolishes antibody cross-reactivity. Differential cross-reactivity of the Mab with STh and STp peptides, which differ markedly only in their N-termini, suggests that this antibody recognizes a distinct conformation in the two peptides, which is essential for receptor interaction

Item Type:	Journal Article
Publication:	Biochimica et Biophysica Acta
Publisher:	Elsevier
Additional Information:	Copyright of this article belongs to Elsevier.
Keywords:	Heat-stable enterotoxin;Human ST receptor;T84 cell;Monoclonal antibody.
Department/Centre:	Division of Biological Sciences > Molecular Reproduction, Development & Genetics
Date Deposited:	05 Mar 2009 09:46
Last Modified:	19 Sep 2010 05:26
URI:	http://eprints.iisc.ac.in/id/eprint/18987

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